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CLICK Decision Memo for
Continuous Positive Airway Pressure (CPAP) Therapy for
Obstructive Sleep Apnea (OSA) (CAG-00093R2)
Decision Memo
TO: Administrative File: CAG #00093R2 Continuous Positive
Airway Pressure (CPAP) Therapy for Obstructive Sleep Apnea (OSA)
FROM:
Steve Phurrough, MD, MPA
Director, Coverage and Analysis Group
Louis Jacques, MD
Director, Division of Items and Devices
Francina Spencer
Lead Analyst
Jean Stiller, MA
Analyst
Ross Brechner, MD, MS (Stat.), MPH
Lead Medical Officer
SUBJECT: Coverage Decision Memorandum for Continuous
Positive Airway Pressure (CPAP) Therapy for Obstructive Sleep
Apnea (OSA) (CAG-00093R2)
DATE:
March 13, 2008
I. Decision
We received a request to reconsider the 2005 National Coverage
Determination (NCD) for CPAP Therapy for OSA
(CAG-00093R) to allow coverage of CPAP based upon a diagnosis of
OSA by home sleep testing (HST). After
considering public comments and additional information, we are
making the following changes to the NCD for CPAP.
The revised indications and limitations NCD are noted in
Appendix B.
1.
Coverage of CPAP is initially limited to a 12 week period for
beneficiaries diagnosed with OSA as
subsequently described. CPAP is subsequently covered for those
beneficiaries diagnosed with OSA whose OSA
improved as a result of CPAP during this 12 week period.
We remind the reader that Durable Medical Equipment,
Prosthetics, Orthotics, and Supplies (DMEPOS)
suppliers are required to provide beneficiaries with necessary
information and instructions on how to use
Medicare-covered items safely and effectively. 42 CFR
424.57(c)(12). Failure to meet this standard may result
in revocation of the DMEPOS supplier’s billing privileges. 42
CFR 424.57(d).
2.
CPAP for adults is covered when diagnosed using a clinical
evaluation and a positive:
a.
polysomnography (PSG) performed in a sleep laboratory; or
b.
unattended home sleep monitoring device of Type II; or
c.
unattended home sleep monitoring device of Type III; or
d.
unattended home sleep monitoring device of Type IV, measuring at
least three channels
We remind the reader that, in general, pursuant to 42 CFR
410.32(a) diagnostic tests that are not ordered by the
beneficiary’s treating physician are not considered reasonable
and necessary. Pursuant to 42 CFR 410.32(b)
diagnostic tests payable under the physician fee schedule that
are furnished without the required level of
supervision by a physician are not reasonable and necessary.
3.
A positive test for OSA is established if either of the
following criterion using the Apnea-Hypopnea Index
(AHI) or Respiratory Disturbance Index (RDI) are met:
AHI or RDI greater than or equal to 15 events per hour, or
.
AHI or RDI greater than or equal to 5 and less than or equal to
14 events per hour with documented
symptoms of excessive daytime sleepiness, impaired cognition,
mood disorders or insomnia, or
documented hypertension, ischemic heart disease, or history of
stroke.
The AHI is equal to the average number of episodes of apnea and
hypopnea per hour. The RDI is equal to the
average number of respiratory disturbances per hour.
4.
If the AHI or RDI is calculated based on less than two hours of
continuous recorded sleep, the total number of
recorded events to calculate the AHI or RDI during sleep testing
is at least the number of events that would
have been required in a two hour period.
5.
We are deleting the distinct requirements that an individual
have moderate to severe OSA and that surgery is a
likely alternative.
6.
CPAP based on clinical diagnosis alone or using a diagnostic
procedure other than PSG or Type II, Type III, or
a Type IV HST measuring at least three channels is covered only
when provided in the context of a clinical
study when that study meets the following standards:
A clinical study seeking Medicare payment for CPAP provided to
the beneficiary pursuant to Coverage with
Evidence Development (CED) must address one or more of the
following questions:
a.
In Medicare aged subjects with clinically identified risk
factors for OSA, how does the diagnostic
accuracy of a clinical trial of CPAP compare with PSG and Type
II, III & IV HST in identifying
subjects with OSA who will respond to CPAP?
b.
In Medicare aged subjects with clinically identified risk
factors for OSA who have not undergone
confirmatory testing with PSG or Type II, III & IV HST, does
CPAP cause clinically meaningful harm?
The study must meet the following additional standards:
c.
The principal purpose of the research study is to test whether a
particular intervention potentially
improves the participants’ health outcomes.
d.
The research study is well-supported by available scientific and
medical information or it is intended to
clarify or establish the health outcomes of interventions
already in common clinical use.
e.
The research study does not unjustifiably duplicate existing
studies.
f.
The research study design is appropriate to answer the research
question being asked in the study.
g.
The research study is sponsored by an organization or individual
capable of executing the proposed
study successfully.
h.
The research study is in compliance with all applicable Federal
regulations concerning the protection of
human subjects found at 45 CFR Part 46. If a study is regulated
by the Food and Drug Administration
(FDA), it also must be in compliance with 21 CFR Parts 50 and
56.
i.
All aspects of the research study are conducted according to the
appropriate standards of scientific
integrity.
j.
The research study has a written protocol that clearly
addresses, or incorporates by reference, the
Medicare standards.
k.
The clinical research study is not designed to exclusively test
toxicity or disease pathophysiology in
healthy individuals. Trials of all medical technologies
measuring therapeutic outcomes as one of the
objectives meet this standard only if the disease or condition
being studied is life-threatening as defined
in 21 CFR § 312.81(a) and the patient has no other viable
treatment options.
l.
The clinical research study is registered on the
ClinicalTrials.gov website by the principal
sponsor/investigator prior to the enrollment of the first study
subject.
m.
The research study protocol specifies the method and timing of
public release of all pre-specified
outcomes to be measured including release of outcomes if
outcomes are negative or study is terminated
early. The results must be made public within 24 months of the
end of data collection. If a report is
planned to be published in a peer-reviewed journal, then that
initial release may be an abstract that meets
the requirements of the International Committee of Medical
Journal Editors. However, a full report of
the outcomes must be made public no later than three (3) years
after the end of data collection.
n.
The research study protocol must explicitly discuss
subpopulations affected by the treatment under
investigation, particularly traditionally underrepresented
groups in clinical studies, how the inclusion
and exclusion criteria affect enrollment of these populations,
and a plan for the retention and reporting
of said populations on the trial. If the inclusion and exclusion
criteria are expected to have a negative
effect on the recruitment or retention of underrepresented
populations, the protocol must discuss why
these criteria are necessary.
o.
The research study protocol explicitly discusses how the results
are or are not expected to be
generalizable to the Medicare population to infer whether
Medicare patients may benefit from the
intervention. Separate discussions in the protocol may be
necessary for populations eligible for Medicare
due to age, disability or Medicaid eligibility.
Consistent with section 1142 of the Social Security Act (the
Act), the Agency for Healthcare Research
and Quality (AHRQ) supports clinical research studies that the
Centers for Medicare and Medicaid
Services (CMS) determines meet the above-listed standards and
address the above-listed research
questions
II. Background
We use the abbreviation PSG to refer to attended polysomnography
or an attended polysomnogram depending on the
context of the sentence, unless we specifically describe an
unattended use. We use the abbreviation HST to refer to
35unattended multichannel home sleep testing or multichannel
home sleep monitoring.
OSA, sometimes referred to as Obstructive Sleep Apnea Hypopnea
Syndrome-OSAHS, is associated with significant
morbidity and mortality. It is a commonly underdiagnosed
condition that occurs in 4% of men and 2% of women
(Young et al. 1993). The prevalence increases with age (up to
10% in persons 65 and older), as well as with increased
weight. Complications associated with OSA include excessive
daytime sleepiness, concentration difficulty, coronary
artery disease, and stroke (Kokturk et al. 2005). It is
estimated that 10% of patients with congestive heart failure (CHF)
have OSA, which is independently associated with systemic
arterial hypertension (Caples et al. 2005). Untreated OSA
is associated with a ten-fold increased risk of motor vehicle
accidents (Teran-Santos et al. 1999). The most common
clinical presentation of patients with OSA is obesity
accompanied by excessive daytime drowsiness (20% of adults
with Body Mass Index (BMI) > 30 have OSA), although other
clinical findings associated with OSA include nocturnal
choking or gasping, witnessed apneas during sleep, large neck
circumference and daytime fatigue.
Of the three different forms of sleep apnea (obstructive,
central, or mixed), OSA is the most common. Patients
suffering with sleep apnea may literally stop breathing (apnea)
or have decreased breathing (hypopnea), repeatedly
during sleep. The apnea episodes often last for a minute or
longer, and can occur hundreds of times during a single
night’s sleep. During the obstructive apnea episodes, either
complete or partial obstruction of the airway occurs. The
anatomic site of obstruction is thought to be the soft palate,
extending to the base of the tongue. When patients with
OSA fall asleep, muscles of this region relax to the point of
permitting airway collapse and obstruction. When the
airway closes, breathing stops and the sleeper awakens to open
the airway. Arousals from sleep usually last only a few
seconds, but these brief arousals disrupt continuous sleep and
prevent persons from reaching deep stages of sleep (e.g.,
rapid eye movement sleep-REM), which is necessary in order for
the body to rest and replenish strength. The patient
repeats this cycle throughout the sleep period.
Diagnosis
OSA has been often defined by an AHI of > 5 events per hour
during sleep (when using this less restrictive definition,
the prevalence may be as high as 25% of the population) or by a
higher threshold e.g. AHI of > 15 events per hour (the
prevalence is as reported above). Medicare has covered CPAP for
the treatment of OSA if the beneficiary has an AHI
greater than or equal to 5 events and less than or equal to 14
events per hour with a co-morbidity related to OSA, or an
AHI > 15 events per hour without a co-morbidity related to OSA.
The key diagnostic finding in OSA is episodes of
airflow cessation or reduction at the nose and mouth despite
evidence of continuing respiratory effort.
Other common clinical findings used by physicians in the
diagnosis of OSA include oxygen desaturation, abnormal
oxygen desaturation index, and RDI which represents the total
number of apneas and hypopneas in the total sleep
period divided by the total number of hours in the sleep period.
There is no universally accepted definition of either
oxygen desaturation or abnormal oxygen desaturation index in
sleep-disordered breathing. Other measures such as
arterial pulsatile volume changes, measurement of airflow,
measurement of breathing patterns, Multiple Sleep Latency
Testing (MSLT) and Maintenance of Wakefulness Testing,
computerized electroencephalogram (EEG) analysis,
autonomic arousal detection, and body movement analysis are some
of the measures currently being employed by
physicians for diagnosis of OSA.
Diagnostic tests for OSA have historically been classified into
four types. The most comprehensive is designated
Type
I: attended, or in-facility PSG, which is considered the
reference standard for diagnosing OSA. Three categories of
portable monitors (used both in attended and unattended
settings) have been developed for the diagnosis of OSA.
Type
II monitors have a minimum of 7 channels (e.g., EEG, EOG, EMG,
ECG-heart rate, airflow, respiratory effort, oxygen
saturation-this type of device monitors sleep staging, so
calculation of AHI can be calculated).
Type III monitors have a
minimum of 4 monitored channels including ventilation or airflow
(at least two channels of respiratory movement or
respiratory movement and airflow), heart rate or ECG, and oxygen
saturation.
Type IV devices do not meet the
requirements of other types, and many measure only one or two
parameters (e.g., oxygen saturation or airflow) but
some Type IV devices measure three or more parameters. There are
other technologies that do not readily fall into the
classification above.
Overnight PSG is the conventional diagnostic test for OSA. The
American Thoracic Society (ATS 1994) and the
American Academy of Sleep Medicine (AASM 1997) recommend
supervised PSG in the sleep laboratory over 2 nights
for the diagnosis of OSA and the initiation of CPAP.
According to Harrison’s Principles of Internal Medicine (2005):
…the definitive investigation for suspected OSA is
polysomnography (PSG), a detailed overnight sleep study that
includes recording of (1) electrographic variables
(electroencephalogram, electrooculogram, and submental
electromyogram) that permits the identification of sleep and its
various phases, (2) ventilatory variables that permit the
identification of apneas and their classification as central or
obstructive, (3) arterial O2 saturation by ear or finger
oximetry, and (4) heart rate.”
Young et al. (1999) note limited capacity to provide PSG testing
to all persons with symptoms of OSA due to the high
prevalence of OSA. Some studies have noted false-negative rates
of 14 to 25% (Le Bon et al. 2000; Littner 2000). And
35as noted by Klingshott et al. (2000) associates, the measures
derived from PSG (e.g., AHI) correlate poorly with major
consequences of OSA such as sleepiness and cognitive impairment.
Loube et al. (1999) and others have also noted that
these measures do not reliably predict the response to the
standard therapy for OSA, nasal CPAP.
PSG alternatives have been sought. Predictive algorithms
(predictive formulae) to determine optimal CPAP (Flemons
et al. 1994; Maislin et al. 1995; Rowley et al. 2000), screening
oximetry (Whitlaw et al. 2005; Chiner et al. 1999),
attended/unattended home diagnostic apnea monitoring devices (Sériés
et al 1993; Golpe et al. 2002; Whitelaw et al.
2005), and questionnaires (e.g., Epworth Sleepiness Scale; Sleep
Apnea Clinical Scores) have been developed to help
make a sensitive and specific diagnosis of OSA. Other strategies
that have been suggested to reduce the delay,
inconvenience and expense associated with sleep studies include
split night studies (Yamashiro et al. 1995), partner
titration, and home stepwise titration. These items have been
proposed as a diagnostic aid for patients with a high
suspicion of OSA (Ballester et al. 2000; Ficker et al. 2001;
Ross et al. 1998; Verse Pirsig et al. 2000).
As noted in Harrison’s Principles of Internal Medicine:
Because PSG is a time-consuming and expensive test, there is
considerable interest in the role of a screening test and of
unattended home sleep-monitoring for the investigation of OSA,…in
patients with a high probability of OSA (based on
history of habitual snoring, nocturnal choking or gasping,
witnessed apnea during and daytime sleepiness), overnight
recordings of arterial O2 arterial saturation by oximetry can be
used to confirm the diagnosis and obviate the need for
full PSG by demonstrating recurrent episode of desaturation (at
least 10 to 15 events per hour).
Treatment of OSA
A number of treatment approaches have been recommended for
patients with OSA, depending on severity of the
disorder (e.g., the degree of clinical symptoms), as well as the
objective level of nocturnal respiratory and sleep
disturbance (e.g., daytime sleepiness or number of obstructive
events per hour of sleep). For patients with severe OSA,
nasal CPAP is the treatment of choice. Its regular use improves
excessive sleepiness, cognitive performance, and
quality of life (Jenkinson et al. 1999; Montserrat et al. 2001).
In patients with severe OSA who can not tolerate nasal
CPAP, surgical procedures (e.g., uvulopalatopharygnoplasty-UPPP,
maxillofacial surgery) may be indicated. In
patients with mild to moderate OSA, nasal CPAP may be indicated,
though conservative measures such as weight
reduction, avoidance of alcohol, avoidance of sleeping in a
recumbent position, or intra-oral appliances may be better
tolerated.
CPAP treatment uses air pressure to maintain airway patency.
There are several types of CPAP devices used in the
treatment of OSA. These include: (1) conventional CPAP devices
which provide a constant, steady air pressure all
night; (2) bi-level positive airway pressure devices, which,
instead of providing a constant pressure throughout the
night, sense inspiration and expiration and vary the level of
pressure accordingly; and (3) responsive ("smart") airway
pressure devices that incorporate flow and pressure sensors and
automatic regulation systems to continuously adjust
mask pressure to the actual needs of the patient.
Conventionally, technicians titrate CPAP pressures via a
therapeutic mask pressure (i.e. the minimum pressure that
eliminates abnormal breathing) as determined by manual titration
over the course of a night in a sleep laboratory. But
the long-held belief that fixed-pressure CPAP therapy is the
standard is being challenged. The pressure required to
maintain upper airway patency in patients with OSA varies
throughout the night depending on body position (Jokic,
Klimaszewski et al. 1999), sleep state and other factors. Also,
CPAP requirements may change over time due to
changes in upper airway properties as well as variation in body
weight.
Alternatively, automatic computer-controlled CPAP titration
(auto CPAP) can be performed over one or several nights,
attended or unattended (a technician can be present or absent),
in a sleep laboratory or a home setting. Auto CPAP
devices can be used either for titration only, in order to
choose a single therapeutic pressure that will be used on a
long-
term basis or permanently for adjusting to the patient’s
changing needs. The use of auto-titrating CPAP based on
algorithms has also been evaluated in the treatment of OSA
(Berry et al. 2002; Stammnitz et al. 2004). Auto CPAP
devices adjust pressure by feed-back control according to
patterns of pressure, flow or other signals recorded during
treatment. Information obtained on pressure readings during an
unattended auto CPAP titration may determine
therapeutic pressure for subsequent fixed pressure CPAP. A
number of studies have been done which have shown that
the use of autotitration CPAP machines, as opposed to fixed-flow
CPAP machines, are effective in determining
therapeutic CPAP, and as a method of treatment (Berry et al.
2002; Stammnitz et al. 2004; Massie et al. 2003).
III. History of Medicare Coverage
In 1986, the CMS (then known as the Health Care Financing
Administration) asked the Office of Health Technology
Assessment (OHTA) to conduct an assessment of the safety,
clinical effectiveness and use of CPAP. OHTA reported
that "the consensus of clinical opinion from the available
information appears to be that CPAP can in the majority of
cases prevent OSA and provide substantial clinical improvement
with minimal associated morbidity." They went on
further to recommend that "the use of CPAP be covered under
Medicare when used in adult patients with moderate and
severe OSA who have failed to obtain relief from other
non-invasive therapies and for whom surgery would be the only
other therapeutic alternative." The diagnosis of OSA required at
least 30 episodes of apnea, each lasting a minimum of
3510 seconds, during 6-7 hours of sleep. These specifications
were based predominately on expert opinions at the time.
Based on the OHTA technology assessment (TA), Medicare issued an
NCD (see NCD Manual 240.4) which covered
Date: 6/4/2008, Page 5 of
CPAP for adult patients with moderate or severe OSA for whom
surgery is a likely alternative (effective date January
12, 1987) and adopted OHTA's recommendations on the diagnosis of
OSA. Unattended HST has been reviewed by
CMS since 1989. In 1995, the agency’s reviewing body for the
development of NCDs concluded that the safety and
effectiveness of home studies used to diagnosis sleep disorders
were unproven and thus should not be covered by the
Medicare program. The advisory committee recommended that this
issue be reconsidered for national policy following
the completion of a large study of sleep disorders by the
National Institutes of Health. This study was to include an
evaluation of in-home testing. The study was expected to be
completed within two to three years. Therefore, the
coverage of unattended HST was left to carrier discretion.
In 2001, the national coverage policy on CPAP was expanded to
include Medicare beneficiaries with an AHI of > 15,
or an AHI > 5 and < 14 with documented symptoms of excessive
daytime sleepiness, impaired cognition, mood
disorders or insomnia, or documented hypertension, ischemic
heart disease or history of stroke. However, the policy
specified that only PSG done in a facility-based sleep study
laboratory could be used to identify patients with OSA.
In 2005, CMS determined that the evidence was not adequate to
conclude that the use of unattended portable multichannel
sleep testing with a minimum of 7 monitored channels including
EEG, EOG, EMG, ECG or heart rate, airflow,
respiratory effort, and oxygen saturation (Type II devices based
on the 1994 ASDA classification) was reasonable and
necessary in the diagnosis of OSA and these tests remain
noncovered for the diagnosis of OSA.
Current Request
CMS reviewed its NCD regarding the diagnosis of patients with
OSA requiring CPAP therapy. (NCD 240.4).
CMS received a complete formal written request from the American
Academy of Otolaryngology-Head and Neck
Surgery to modify this decision to include the use of portable
multi-channel HST devices as an alternative to facility-
based PSG in the evaluation of OSA.
In addition, CMS received an incomplete request from a Medicare
beneficiary, numerous informal requests from
stakeholders, and interest from Medicare contractors concerning
the criteria for determining the AHI. The current NCD
at section 240.4 states in part "…The AHI is equal to the
average number of episodes of apnea and hypopnea per hour
and must be based on a minimum of 2 hours of sleep recorded by
polysomnography using actual recorded hours of
sleep (i.e. the AHI may not be extrapolated or projected)." It
has been suggested by some that this requirement be
changed to "the AHI is equal to the average number of episodes
of apnea and hypopnea per hour and must be based on
a minimum of 2 hours of sleep or less, if the actual number of
AHI episodes recorded is 30 or more in less than 2 hours,
recorded by polysomnography using actual recorded hours of
sleep” (i.e., the AHI may not be extrapolated or
projected).
We are also aware of recently published research suggesting a
benefit for the use of CPAP without prior sleep testing in
selected populations (trial of CPAP).
The scope of this reconsideration includes all aspects of this
prior NCD.
Benefit Category
Medicare is a defined benefit program. All services furnished
under the Medicare program must be medically
reasonable and necessary, and appropriate for diagnosis and/ or
treatment of an illness or injury. Furthermore,
physicians and nonphysician practitioners must be authorized by
the State in which the services are furnished to render
the services. An item or service must fall within a benefit
category as a prerequisite to Medicare coverage: § 1812
(Scope of Part A); § 1832 (Scope of Part B); § 1861(s)
(Definition of Medical and Other Health Services).
A CPAP device falls within the DME benefit category found at
section 1861(s)(6) of the Act. Regulations found at 42
CFR 414.202 describe DME as equipment furnished by a supplier or
a home health agency that: (1) can withstand
repeated use; (2) is primarily and customarily used to serve a
medical purpose; (3) generally is not useful to an
individual in the absence of a illness or injury; (4) is
appropriate for use in the home.
CMS considers diagnostic testing to be the appropriate coverage
category for PSG and multichannel HST.
IV. Timeline of Recent Activities
March 14, 2007 CMS posted a tracking sheet on the website and
the initial 30 day
public comment period began.
May 29, 2007 CMS announced that it would convene the Medicare
Evidence
Development and Coverage Advisory Committee (MedCAC) to
consider this issue on Tuesday, September 12, 2007 from 7:30
a.m.
until 4:30 p.m. EST at CMS, 7500 Security Blvd, Baltimore, MD
21244.
June 25, 2007 CMS posted initial comments received
September 12, 2007 CMS held a MedCAC meeting.
Date: 6/4/2008, Page 6 of
December 14, 2007 CMS published a proposed decision and opened a
30 day public
comment period.
January 13, 2008 Public comment period ended
V. FDA Status
HST devices and other similar devices, such as multi-channel HST
and other related devices have been considered and
cleared for marketing by the FDA under a 510(k) process. The
510(k) is a notification of intent to market a specific
device. The FDA has determined that certain HST devices are
"substantially equivalent to legally marketed predicate
devices marketed in interstate commerce prior to May 28, 1976,
enactment date of the Medical Device Amendments, or
to devices that have been reclassified in accordance with the
provisions of the Federal Food, Drug, and Cosmetic Act."
A substantially equivalent determination assumes compliance with
the Good Manufacturing Practice requirements, as
set forth in the Quality System Regulation (QS) for Medical
Devices: General regulation (21 CFR Part 820) and that,
through periodic QS inspections, the FDA will verify such
assumptions. Failure to comply with the GMP regulation
may result in regulatory action. Typically, no clinical data is
required as part of the 510 (k) application, but instead the
clearance process focuses on technical performance. However, the
FDA does request clinical data for snore validation
as well as event detection (i.e. clinical validation that the
apneas or hypopneas detected are also scored as apneas or
hypopneas by a manual scorer). The FDA also compares sensitivity
and positive predictive values to a predicate device.
The FDA has cleared numerous types of CPAP devices for use in
the home under the 510(k) process. These include but
are not limited to many devices that allow a patient to wear a
device that collects airflow and other patient
measurements into a device that records data, while treating OSA
with that device. The patient then takes the device to
the physician and the physician downloads information that
determines whether the patient has an apnea sleep-related
breathing disorder including OSA or needs further sleep studies
or assessment.
VI. General Methodological Principles
When making NCDs, CMS evaluates relevant clinical evidence to
determine whether or not the evidence is of
sufficient quality to support a finding that an item or service
falling within a benefit category is reasonable and
necessary for the diagnosis or treatment of illness or injury or
to improve the functioning of a malformed body member.
The critical appraisal of the evidence enables us to determine
to what degree we are confident that: 1) the specific
assessment questions can be answered conclusively; and 2) the
intervention will improve health outcomes for Medicare
beneficiaries. An improved health outcome is one of several
considerations in determining whether an item or service is
reasonable and necessary under § 1862(a)(1)(A) of the Act.
A detailed account of the methodological principles of study
design that are used to assess the relevant literature on a
therapeutic or diagnostic item or service for specific
conditions can be found in Appendix A. In general, features of
clinical studies that improve quality and decrease bias include
the selection of a clinically relevant cohort, the
consistent use of a single good reference standard, and the
blinding of readers of the index test, and reference test
results.
Public comment sometimes cites the published clinical evidence
and gives CMS useful information. Public comments
that give information on unpublished evidence such as the
results of individual practitioners or patients are less
rigorous and therefore less useful for making a coverage
determination. CMS uses the initial public comments to
inform its proposed decision. CMS responds in detail to the
public comments on a proposed decision when issuing the
final decision memorandum.
VII. Evidence
A. Introduction
We are providing a summary of the evidence that we considered
during our review. CMS held a MedCAC meeting on
September 12, 2007 and commissioned external TAs from the AHRQ
to review published clinical evidence on the use
of devices in the diagnosis of OSA and to do modeling of
different scenarios of diagnosis. CMS reviewed information
and recommendations provided as a result of the MedCAC meeting,
the TAs provided by AHRQ, and conducted its
own independent search and review of individual clinical studies
addressing this issue. CMS also reviewed other
information from professional societies and other
groups/organizations, searched evidence based practice
guidelines,
consensus statements, and position papers.
We sought to determine if new evidence supports conclusions that
differ from those in the NCD on this topic that we
published in early 2005. For HST we focused on evidence
published since the 2004 Medicare Coverage Advisory
Committee (MCAC) meeting and the 2005 reconsideration of this
NCD. Because we had not previously reviewed the
evidence pertinent to clinical diagnosis alone, our review of
that literature included evidence predating our 2005
decision.
B. Discussion of evidence reviewed
1. Questions & Outcomes
Date: 6/4/2008, Page 7 of
Question 1: Is the evidence adequate to determine that
diagnostic strategies other than facility based PSG accurately
identifies patients with OSA who will benefit from CPAP
treatment?
Question 2: Is the evidence adequate to determine that the
accurate diagnosis of OSA requires at least two hours
continuous recorded sleep?
Question 3: Is diagnosis of OSA by clinical criteria alone
sufficient for the use of CPAP in the absence of either
a
positive PSG or a positive unattended multichannel home sleep
test?
As diagnostic tests, PSG and HST would not be expected to
directly change health outcomes. Rather, a diagnostic test
affects health outcomes through changes in disease management
brought about by physician actions taken in response
to test results. Such actions may include decisions to treat or
withhold treatment, to choose one treatment modality over
another, or to choose a different dose or duration of the same
treatment. To some extent the usefulness of a test result is
constrained by the available treatment options. As noted in the
Background section, the number of practical treatment
options for OSA is limited. Most patients get CPAP; a few get
oral appliances or surgery. A patient whose OSA is not
readily controlled with CPAP may seek other treatment, continue
CPAP with lesser benefit, or discontinue CPAP and
not seek further medical treatment. In addressing the questions
above, one of the factors we considered is whether there
is sufficient evidence that the incremental information derived
from PSG or HST leads to improved treatment of OSA
by causing physicians to prescribe a different treatment than
they would have prescribed without access to the test
results.
The choice of specific treatment is influenced by many factors
other than its predicted ability to reduce sleep apnea.
Some patients may prefer to avoid a surgical intervention. Other
patients may have comorbid conditions such as
chronic cardiac or respiratory disease that will influence the
use or avoidance of certain treatments.
Outcomes of interest for a diagnostic test are not limited to
determining its accuracy but also include beneficial or
adverse clinical effects, such as changes in management due to
test findings or preferably, improved health outcomes
for Medicare beneficiaries. Ideally, we would see evidence that
the systematic incorporation of PSG or HST results into
a treatment algorithm leads treating physicians to prescribe
different and better treatment than they would otherwise
have prescribed, and that those patients whose treatment is
changed by test results remain on the regimen and achieve
better long term OSA control documented by repeated assessments
over time.
There is no anatomic or physiologic "gold standard" for the
diagnosis of OSA, in contrast to conditions such as cancer
where a tissue biopsy result is the definitive standard
reference. In studies that compare HST to facility-based PSG,
the
investigators have used the PSG result as the standard
reference, i.e. the PSG result is used to define the true
disease
state for the individual patient. This is less than ideal since
the true sensitivity and specificity of PSG in diagnosing
OSA is not well documented, and this deficiency poses a
practical difficulty in diagnosing OSA. Given the absence of a
true "gold standard" reference, the clinical application of
terms such as sensitivity and specificity is not
straightforward.
Such evidence permits only the comparison of HST to
facility-based PSG. It is problematic to make the inferential
leap
from there to a judgment on the ability of HST or PSG to
accurately identify those patients who will, if untreated with
CPAP, suffer the morbidity and mortality of OSA. If an
individual patient has conflicting results with these two tests,
e.g. a negative HST in the face of a positive PSG, there is no
available higher reference to determine whether the
conflict arises from a false negative HST or a false positive
PSG.
2. External TAs
Systematic reviews are based on a comprehensive search of
published studies to answer a clearly defined and specific
set of clinical questions. A well-defined strategy or protocol
(established before the results of the individual studies are
known) guides this literature search. Thus, the process of
identifying studies for potential inclusion and the sources for
finding such articles is explicitly documented at the start of
the review. Finally, systematic reviews provide a detailed
assessment of the studies included. CMS commissioned two TAs
from AHRQ:
•
Home diagnosis of OSA-Hypopnea Syndrome, and
•
OSA-Hypopnea Syndrome: modeling different diagnostic strategies
We summarize them below. The full reports are available at the
following CMS website:
http://www.cms.hhs.gov/mcd/viewtechassess.asp?id=204.
Home diagnosis of OSA-Hypopnea Syndrome (OSAHS)
Ninety-three studies were included in a review of the
literature. Eligible studies assessed the ability of sleep
studies at
baseline to predict response to CPAP treatment or CPAP use, the
comparison of measurements with portable monitors
and facility-based PSG, and the safety of sleep studies.
The TA reported that the reference standard for the diagnosis of
OSAHS is facility-based PSG, a comprehensive sleep
study that records and evaluates a variety of cardiorespiratory
and neurophysiologic signals during sleep time. It
35quantifies the severity of disturbances with the Apnea-Hypopnea
Index (AHI). Higher AHI values imply more severe
sleep disturbances. Typically, a value of 15 events/hour of
sleep or more is considered to be suggestive of OSAHS. An
Date: 6/4/2008, Page 8 of
AHI suggestive of OSAHS is neither sufficient nor necessary for
the diagnosis of the condition, as the severity of
symptoms has to be accounted for, and other conditions affecting
sleep may need to be excluded. Baseline AHI is only
modestly associated with response to CPAP or CPAP use among
people with high (pre-test) probability for OSAHS.
The same is true for other indices obtained from sleep studies
such as the mean or minimum O2 saturation, apnea index,
hypopneas index, frequency of arousals and other quantities.
Based on limited data, the authors conclude that type II
monitors may identify AHI suggestive of OSAHS with high
positive likelihood ratios (> 10) and low negative likelihood
ratios (< 0.1) both when the portable monitors were
studied in the sleep laboratory and at home. Type III monitors
may have the ability to predict AHI suggestive of
OSAHS with high positive likelihood ratios and low negative
likelihood ratios for various AHI cutoffs in laboratory-
based PSG, especially when manual scoring is used. The ability
of type III monitors to predict AHI suggestive of
OSAHS appears to be better in studies conducted in the
specialized sleep unit compared to studies in the home setting.
Some studies of type IV monitors also showed high positive
likelihood ratios and low negative likelihood ratios, at
least for selected sensitivity and specificity pairs from ROC
curve analyses. As with type III monitors, the ability of
type IV monitors to predict AHI suggestive of OSAHS appears to
be better in studies conducted in specialized sleep
units. Medicare beneficiaries are older than the studied
subjects (the median average age was approximately 50 years in
the analyzed studies), and may more often have conditions other
than OSAHS that affect sleep (e.g., Periodic Limb
Movements in Sleep and Restless Leg Syndrome; cardiac
insufficiency). These conditions may be misdiagnosed as
OSAHS by sleep monitors that do not record channels necessary
for the differential diagnosis from OSAHS. Therefore,
some type III and type IV monitors may yield more false
positives among Medicare beneficiaries, compared to what
was observed in the assessed studies. For studies in the home
setting, there are no direct data on whether and to what
extent technologist support and patient education affect the
comparison of portable monitors with facility-based PSG.
For monitors that may be considered other than Type II, III, or
IV the authors found there is insufficient evidence to
judge their value in diagnosing OSA. The TA differentiated Type
IV monitors with three or more channels from those
with one or two channels, finding greater diagnostic ability for
the former. We note that the TA reviewed the WatchPAT100
device as a Type IV device with three or more channels.
OSA-Hypopnea Syndrome: modeling different diagnostic strategies
The TA authors created a model to test the impact of different
OSA strategies. When middle-aged people (50 years old)
with symptoms and signs suggestive of OSAHS are tested in the
home setting, approximately 10 percent of those with
OSAHS are expected to remain undiagnosed; approximately 15
percent of those without OSAHS receive false-positive
diagnoses. For older adults (70 years old) the expected number
of misclassifications is larger, due to the expected
increase in false positive diagnoses (30 percent). With the
combination strategy that uses home diagnosis and split-
night PSG almost 20 percent of middle-aged people with OSAHS
received a (false) negative diagnosis, while the
proportion of false positive results among 50 year-old people
without OSAHS was very low (1 percent). The expected
numbers were similar among older adults (70 years old).
Both for middle-aged people and for older adults, the average
time spent undiagnosed is practically negligible for the
strategies that use home monitoring. In the combination
strategy, people with positive diagnosis with the portable
monitors receive a final split-night PSG diagnosis within 15
weeks on average.
When diagnosis of OSAHS and treatment initiation are managed
outside the sleep laboratories in the home setting,
middle-aged people with OSAHS spend on average 10 weeks or 9
percent of the total follow up time in undiagnosed
health states. Indicatively, the corresponding mean time delay
for middle-aged people is 27 weeks when they are
managed with facility-based PSG. This number mainly reflects
those with false negative diagnoses, who are never
started on CPAP. The same is expected among older adults (70
years old).
With the combination strategy, using home diagnosis and
split-night PSG, correctly diagnosed people initiate on CPAP
after approximately 15 weeks. However, one fifth of the patients
are not diagnosed and, overall, the average time spent
while not on CPAP ("high-risk" states) becomes 33 weeks. Similar
numbers are expected among older adults who have
OSAHS.
3. Internal TAs
Literature Search
CMS performed an extensive literature search utilizing PubMed
for randomized controlled trials (RCTs), systematic
reviews, and series studies evaluating the use of PSG, HST, CPAP
trial, and clinical diagnosis of OSA. The literature
search was limited to humans. Though we focused our search on
evidence published since the 2004-2005
reconsideration of this NCD we looked at relevant studies before
that time frame.
There are currently several proposed mechanisms to diagnosis OSA
and determine the need for and benefit of CPAP.
These include clinical diagnosis alone, PSG, home testing with
various devices and a diagnosis made by using a trial of
CPAP. We will address the evidence for each individually.
Clinical Diagnosis
Crocker et al. (1990) studied whether the number of PSGs
required for diagnosis of OSA could be reduced in the
35
Date: 6/4/2008, Page 9 of
population. They enrolled 100 consecutive patients (average age
50) screened by family and sleep physicians. The
patients were then tested by PSG. A clinical model was created
for predicting a diagnosis of OSA as compared to PSG
and was applied to the next 114 consecutive patients. The model
correctly classified 33 of 36 persons with OSA by
correctly predicting an AHI > 15 and it correctly classified 35
of 69 patients by correctly predicting an AHI < 15. In the
model, BMI, reported apnea, age, and hypertension were
statistically significant factors. The model had a sensitivity
of
92% for predicting OSA when compared to PSG and a specificity of
51%. The authors concluded that clinical
observation might reduce the need for PSG in the diagnosis of
OSA by one-third.
Deegan et al. (1996) compared the predictive value of certain
clinical features to PSG for a diagnosis of OSA. Two
hundred fifty consecutive patients (average age 45) were
pre-screened by a physician and had a clinical assessment and
administration of a sleep questionnaire, along with PSG. One
hundred thirty six (54%) had an AHI > 15 (considered
positive for a diagnosis of OSA) and 114 (46%) had an AHI < 15
(not considered positive for OSA). Using clinical
features and oximetry, 32.4% of patients could be confidently
categorized, compared to PSG, as either having a true
diagnosis of OSA or not having OSA. Significant factors in the
model were BMI, alcohol intake, and age. The authors
concluded that clinical observation may reduce the need for PSG
in the diagnosis of OSA by approximately one-third.
Haponik et al. (1984) asked whether or not PSG is necessary to
assess the presence and severity of sleep-disordered
breathing. They enrolled 37 patients (average age 50) with
clinically suspected OSA, administered a questionnaire and
did PSG testing. Compared to PSG (AHI > 15 as cutoff for
positive diagnosis of OSA) the clinical testing information
had a sensitivity of 64% for a correct diagnosis of OSA and a
specificity of 100%. The authors concluded that a single,
brief clinical observation alone is an ineffective screening
procedure for detecting OSA.
Julià-Serdà et al. (1984) enrolled 225 consecutive referrals to
a sleep clinic (average age 45 in the non-OSA group and
52 in the OSA group) with suspected OSA to determine whether or
not cephalometry was useful in sparing PSG. All
subjects had clinical assessment with an ESS questionnaire,
physical exam and history. In addition they also had
spirometry, cephalometry, and PSG testing. A statistical model
was built to estimate a patient’s probability of a correct
diagnosis of OSA as compared to PSG (using a cutoff value of AHI
> 10), based on clinical variables, physical
examination, pulse oximetry, cephalometry, and soft palate and
uvula measurements. The sensitivity of the model for a
correct diagnosis of OSA as compared to PSG was 93% and the
specificity was 83%. The authors concluded that
cephalometry plus oximetry plus history and physical exam is
capable of sparing the need for PSG in diagnosing OSA.
In 99 pre-operative Laparoscopic Adjustable Gastric Banding
patients with average age in their four groups ranging
from 35 to 44, Dixon et al. (1997) attempted to create a
clinical model for predicting a correct diagnosis of OSA as
compared to PSG. A thorough sleep history and physical
examination were performed, checking for symptoms such as
nocturnal choking, waking unrefreshed, morning headaches,
excessive daytime sleepiness and poor sleep quality. An
ESS was administered and all patients had a PSG test. The PSG
was hand scored. For a PSG cutoff of AHI > 15,
independent predictors for a diagnosis of OSA were observed
sleep apnea (the only positive symptom predictor of an
AHI > 15), male sex, higher BMI, age, fasting insulin and
glycosylated hemoglobin A1c. From the model created, a
scoring mechanism was established and a score of > 3 had a
sensitivity of 89% for a correct diagnosis of OSA as
compared to PSG and a specificity of 81% for moderate/severe OSA.
The authors concluded that a simple method of
predicting OSA in severely obese symptomatic subjects can assist
in limiting the use of PSG to those with greater risk
In a rare RCT on the topic of clinical modeling of OSA, Mulgrew
et al. (2007) investigated the utility of a diagnostic
algorithm in conjunction with ambulatory CPAP titration in
initial management of OSA. This open label RCT
compared PSG with ambulatory CPAP titration in high-risk
patients identified by a diagnostic algorithm in a tertiary
referral sleep disorders program. Sixty-eight patients (average
age 52 in the PSG group and 55 in the ambulatory
group) with a high PSG pretest probability of moderate to severe
OSA (AHI > 15) were identified by ESS score, Sleep
Apnea Clinical Score and oximetry. Patients were randomly
assigned to PSG or ambulatory titration using a
combination of auto CPAP and overnight oximetry. They were
observed for 3 months.
The main outcome measure was AHI on CPAP as compared to before
CPAP, with secondary outcome measures being
ESS score, quality of life and CPAP adherence. After 3 months,
there was no difference in the primary outcome—AHI
on CPAP (median, 3.2 vs. 2.5; difference, 0.8/h)—between the PSG
and ambulatory CPAP groups. After 3 months,
there were no differences between groups in the secondary
outcomes of ESS score, Sleep Apnea Quality of Life Index,
and CPAP. Of particular note was that adherence to CPAP therapy
was better in the ambulatory group than in the PSG
group. The authors concluded that PSG confers no advantage over
the ambulatory approach in terms of diagnosis and
CPAP titration in initial management of patients with a high
probability of OSA. The authors also concluded that the
ambulatory approach may improve adherence to treatment and that,
when access to PSG is inadequate, the ambulatory
approach can expedite treatment. The authors noted that their
study was confined to a specific population and that more
studies were needed to generalize the conclusions to other
populations.
Lim et al. (2006) performed a study to determine if a clinical
model could be developed to predict OSA diagnosis from
35clinical diagnosis only. Seventy-one consecutive snorers
(average age 44) referred for an evaluation for OSA were
enrolled. OSA status was determined by clinical assessment based
on symptoms suggestive of OSA as well as an ESS
Date: 6/4/2008, Page 10 of
and BMI measurement. A PSG was administered and a clinical
assessment model was created and used in identifying
the ‘non-apneic snorers’ among patients referred with snoring.
The model made use of the ESS score (using a cutoff of
> 15), the BMI (using a cutoff of > 28), and the presence of
symptoms such as nocturnal choking, witnessed apnea,
daytime hypersomnolence or morning headaches. Compared to PSG
using a cutoff of AHI > 10, the model had a
sensitivity of 93.4% and a specificity of 60% for correctly
diagnosing OSA. The authors concluded that identifying
‘non-apneic snorers’ in whom PSG could be avoided can be
correctly accomplished via a clinical assessment if two out
of three of the following are absent: 1) ESS score > 15; 2) a
BMI > 28; and 3) the presence of specified symptoms such
as nocturnal choking, witnessed apnea, daytime hypersomnolence
or morning headaches.
Hoffstein et al. (2006) utilized data from 594 patients with an
average age 47 who were referred to sleep clinic for
suspicion of sleep apnea and were all seen by the same physician
to determine if it was possible to develop a clinical
model to predict a correct diagnosis of OSA from a clinical
exam. A PSG with a cutoff of AHI > 10 was used for the
diagnosis of OSA. The independent predictors of a correct
diagnosis of OSA as compared to PSG were age, sex, BMI,
partner observation of apnea and pharyngeal exam findings
(normal vs abnormal). Compared to PSG, the subjective
(clinical) impression alone showed a sensitivity of 63% for a
correct diagnosis of OSA and a specificity of 60%. The
authors concluded that subjective impression alone is not enough
to reliably identify patients with or without a correct
diagnosis of OSA as compared to PSG.
Garcia et al. (2003) studied whether or not they could predict a
correct diagnosis of OSA with a clinical model. They
enrolled 227 consecutive patients (average age 58) measuring
clinical signs and symptoms and performing a PSG.
They then took the next 102 patients and tested their model for
clinical diagnosis of OSA (total 329). They utilized an
AHI > 30 as a cutoff for a correct diagnosis of OSA. In the
model created, they utilized a cut point of 11 for the ESS
and of 30 for BMI and included other significant and independent
factors of age, sex, BMI, neck circumference history
and the referring physician’s subjective feeling (dichotomized
into ‘yes’ or ‘no’) as to each patient’s probability of
having an AHI > 30. Compared to PSG, the model had a sensitivity
of 80% for a correct diagnosis of OSA and a
specificity of 93%. The authors concluded that prior to
diagnostic tests for OSA; clinical data can be useful for
identifying patients suspected of having AHI > 30.
Kushida et al. (1997) attempted to predict OSA with a
morphometric predictor model. Thirty patients (age range 15-75)
were used to create the model and the model was then
prospectively tested on the first consecutive 300 of a total of
423
patients referred for a diagnosis of OSA. All patients were also
tested with PSG using a cutoff of AHI > 10. The
regression model included oral cavity measurements of the
palatal height by two separate calipers measuring the
distance between the mesial surfaces of the crowns of the second
molars to obtain either the maxillary intermolar
distance or the mandibular intermolar distance. BMI and neck
circumference measurements were also made. The
morphometric model had a sensitivity of 97.6% for a correct
diagnosis of OSA as compared to PSG and a specificity of
100%. The authors concluded that the model may be clinically
useful as a screening tool for OSA rather than as a
replacement for PSG.
To see which snorers referred to a sleep laboratory need PSG for
the diagnosis of OSA, Rauscher et al. (1993) enrolled
98 habitual snorers and 89 patients (average age 58 overall)
with a positive diagnosis of OSA by PSG. A regression
model was created that included weight, height, sex, witnessed
episodes of apnea and falling asleep reading. This
model was applied to 116 consecutive patients referred for
investigation of heavy snoring. All patients with negative
oximetry and a probability value < 0.31 for having OSA had an
AHI < 10 by PSG. The authors concluded that snorers
with negative oximetry classified as not having OSA by this
model do not need PSG.
Viner et al. (1994) examined whether or not history and physical
examination can predict a correct diagnosis of OSA as
compared to PSG. They enrolled 410 patients (average age 50)
referred for clinically suspected OSA. They conducted a
blinded comparison of history and physical examination versus
results of nocturnal PSG utilizing a cutoff point of AHI
> 10. The regression model created included as significant
independent factors age, BMI, sex, witnessed episodes of
apnea and falling asleep reading. They noted that for p < 0.20
(a predicted probability of less than 20% of having OSA)
the clinical model had 94% sensitivity and 28% specificity of
correctly predicting a diagnosis of OSA as compared to
PSG. Subjective impression alone had a sensitivity of 52% and a
specificity of 70% for correctly predicting a diagnosis
of OSA as compared to PSG. The authors concluded that in
patients with a low predicted probability of having a
correct diagnosis of OSA, approximately one-third do not need a
PSG for diagnosis.
Tsai et al. (2002) performed a study to create a decision rule
for diagnostic testing in OSA. They enrolled 75 patients
(average age 47) referred to a sleep clinic for suspicion of
sleep apnea. No mention of consecutive selection was made.
Each patient had portable RDI testing (using a cutoff of RDI >
10) and nocturnal oxygen saturation measurements.
During the feasibility phase, patients underwent routine
clinical assessment plus the upper airway physical examination
protocol (UAPP), performed by two investigators. Unreliable or
time consuming measurements were eliminated from
the UAPP based on clinical judgments and history of snoring and
body position based on the consensus of the two
35investigators. A decision rule was developed using three
predictors: a cricomental space (the perpendicular distance
between the midpoint of the cricomental line, a straight line
from the chin to the cricothyroid cartilage, and the skin of
Date: 6/4/2008, Page 11 of
the neck) of 1.5 cm or less, a pharyngeal grade (I =
palatopharyngeal arch intersects at the edge of the tongue; II =
palatopharyngeal arch intersects at 25% or more of the tongue
diameter; III = palatopharyngeal arch intersects at 50%
or more of the tongue diameter; IV = palatopharyngeal arch
intersects at 75% or more of the tongue diameter) of more
than II and the presence of overbite. For patients with all 3
predictors (17%), the decision rule had a PPV of 95% and
an NPV of 49% for a true diagnosis of OSA by PSG. Comparable
performance was obtained in a validation sample of
50 patients referred for diagnostic testing. The authors
concluded that their decision rule provides a simple, reliable
and
accurate method of identifying a subset of patients with and,
perhaps more importantly, without a true diagnosis of
OSA.
To compare clinical assessment with home oximetry in the
diagnosis of OSA, Guylay et al. (2006) studied 98 nonconsecutive
patients referred to a sleep clinic for suspicion of sleep
apnea. All patients answered a questionnaire, had a
history and physical exam, and had PSG testing using a cutoff
value of AHI > 15 for diagnosis of OSA. Physicians also
independently estimated the likelihood of their patient having a
true diagnosis of OSA on PSG testing. Compared to
PSG, the independent clinical (physician) assessment had a
sensitivity of 79% and a specificity of 50% for correctly
diagnosing OSA at the cutoff value of AHI > 15. Compared to PSG,
oximetry with a desaturation of 2% had a
sensitivity of 65% and a specificity of 74% for diagnosing OSA
at the cutoff value of AHI > 15. For desaturations of
3%, the corresponding sensitivity and specificity were 51% and
90%, respectively. If the percentage of sleep time spent
at SaO2 < 90 was > 1%, the sensitivity for a true diagnosis of
OSA as compared to PSG (AHI > 15) was 93% and the
specificity was 51%. The authors concluded that being at SaO2 <
90 for < 1% of the time on home oximetry practically
excludes OSA.
Pillar et al. (1994) compared a clinical diagnosis of OSA to PSG
(cutoff AHI > 10). Eighty-six patients (average age
47) referred to a sleep clinic for suspicion of OSA were
enrolled. The authors did not mention whether or not the
subjects were consecutively enrolled. All patients answered a
detailed sleep questionnaire, had a brief physical
examination and had PSG testing. Compared to PSG (cutoff AHI >
10), a clinical diagnosis of OSA had a sensitivity of
79% and a specificity of 50%. With regards to the model, the
independent factors for a true diagnosis of OSA were
neck circumference, age, self reporting of apnea and falling
asleep unintentionally. Compared to PSG, the sensitivity
was 92% and the specificity was only 18%. The authors concluded
that clinical evaluation cannot replace PSG.
Laboratory Diagnosis using Polysomnography (Type I)
CMS has previously reviewed the data for diagnosis of OSA using
PSG. We are not readdressing that literature in this
decision.
Home testing for OSA
Types II, III & IV
CMS reviewed the AHRQ TA assessment above and found no
additional evidence on HST for Types II, III & IV
devices with the exception of some evidence reviewed below on
the Watch-PAT100.
Oximetry
Both PSG and HST have an oximetry component, which monitors
oxygen desaturation. A number of authors have
claimed that just using the oximetry component alone can help in
making a diagnosis of OSA (Nuber et al. 2000; Sériés
et al 2005; Sériés et al.1993; Guylay et al. 1993).
As noted above, a number of studies have shown that oximetry
measurement helps the diagnostic accuracy of OSA.
Sériés et al. (1993) performed one of the earliest studies
exploring this relationship. Using 240 consecutive patients
with a confirmed (AHI > 10 on PSG) diagnosis of OSA (all were
clinically suspected of having OSA because of loud
snoring; nocturnal choking and awakenings or apneic events or
all three reported by a bedmate; bad sleep quality; and
daytime hypersomnolence), they found that oximetry had a 98%
sensitivity for diagnosing OSA (AHI > 10), but a
specificity of only 48%.
Magalang et al. (2003) explored the relationship between
oximetry and OSA. They noted that several quantitative
indices derived from overnight pulse oximetry have been used to
predict the presence of OSA: (1) number of episodes
of oxyhemoglobin desaturations below a threshold-usually a 3% or
4% decline below baseline, (2) the cumulative time
spent below an oxyhemoglobin saturation of 90%, and (3) the
[delta] index—a measure of the variability of the
oxyhemoglobin saturation. The researchers wanted to compare
these indices and determine if some combination of
these indices predicted an individual’s AHI as measured by PSG.
Using a derivation group which consisted of 224
consecutive patients, a prediction model was generated based on
AHIs from the calculated quantitative indexes. The
model was further validated using two groups of consecutive
eligible patients (group 1 consisted of 101 patients and
group 2 consisted of 191 patients). All patients underwent
standard overnight PSG and measurement of arterial
oxyhemoglobin (by pulse oximeter).
The major findings of the study revealed that among the
different oximetry indices, the index was the best predictor of
the presence of OSA, though the number of desaturation events
provided similar levels of diagnostic accuracy
35(sensitivity of a index of > 0.63 in the diagnosis of OSA was
91%, while the specificity was 59%). An aggregation of
the model using combinations of all oximetry indices reduced the
prediction error (r2 = 0.70, p < 0.05) compared to
Date: 6/4/2008, Page 12 of
using the index alone (r2 = 0.60), improving the precision of
prediction of the AHI. The correlation between the
predicted and actual AHI was 0.77 when using the index alone,
but improved to 0.83 when using a combination of all
three oximetry indices. The authors note that one limitation of
the study is that the prediction model was validated
using overnight pulse oximetry obtained simultaneously with PSG
data in the sleep laboratory. However, one
advantage of this approach is it eliminated the potential
confounder of night-to-night variability of AHI, as well
ensuring that oximetry data were collected in exactly the same
environment as the PSG data.
Vazquez et al. (2000) studied the diagnostic performance of an
automated digital oximetry analysis based on falls and
recovery of oxygen saturation and compared the results to PSG.
After excluding subjects not eligible for the study, 241
participants with suspected OSA were enrolled in the study and
randomly assigned to either PSG or automated off-line
analysis of the digitally recorded oximetry signal. Study
outcomes included PSG-derived AHI, and oximeter-derived
respiratory disturbance index (RDI). The study revealed that the
PSG-derived AHI and the oximetry-derived RDI were
strongly correlated (R = 0.97); the mean (± 2SD) of the
differences between AHI and RDI was 2.18 (± 12.34)/h. Using
a case definition of 15 episodes/hour for both AHI and RDI, the
sensitivity and specificity were 98% and 88%
respectively. The authors noted that one limitation of the
applicability of this study was that the algorithm was
evaluated by comparison with simultaneous PSGs. They also
commented that a number of studies have shown a
difference in RDI between home and hospital settings, despite
using the same monitor and controlling for technical
difficulty. But the authors were quick to note that by
evaluating patients in the sleep laboratory, potential
confounders
(such as technical difficulties associated with remote
monitoring, night-to-night variability, and the effects of the
home
environment on RDI) are eliminated.
Other
We were asked to perform a separate review of the Watch-PAT100
device, as there has been some uncertainty
expressed about how to classify this device in the current Type
schema. Watch-PAT100 is a HST device which
measures the peripheral arterial tone (PAT) and actigraphy (a
measure of movement) which are recorded with an
ambulatory wrist-worn device (Watch-PAT100). The PAT signal is a
measure of the pulsatile volume changes at the
finger tip reflecting sympathetic tone variations. The algorithm
was developed using a training set of 30 patients
recorded simultaneously with PSG and Watch-PAT100. The
Watch-PAT100 indirectly detects apnea/hypopnea events
by identifying surges of sympathetic activation associated with
the termination of these events. This information is
further combined with heart rate and pulse oximetry data that
are analyzed by the automatic algorithm of the system.
This detects respiratory events and calculates the PAT RDI (PRDI).
We found 19 separate articles, papers, editorials, and fact
sheets addressing this technology. Of these, CMS determined
that 13 were not relevant due to qualities pertaining to sample
size, type of evidence, having not been published in a
peer reviewed journal or not relevant to this data needed for
this NCD. The remaining 6 are reviewed below.
Pittman et al. (2004) aimed at assessing the accuracy of a
wrist-worn device (Watch-PAT 100) to diagnose OSA in the
home. Participants were not consecutive patients but were a
sample of patients who disclosed on a comprehensive
questionnaire between June and December of 2002 that they were
interested in being contacted about research studies
conducted at the sleep laboratory. All 30 subjects completed 2
overnight diagnostic studies with the test device: 1 night
in the laboratory with concurrent polysomnography and 1 night in
the home with only the Watch-PAT100. The mean
age of these subjects was 43.2 ± 10.8 years and mean body mass
index was 33.9 ± 7.1 kg/m2. The mean Epworth
Sleepiness Scale score was 9.2 ± 4.7 (range 2-18). The order of
the laboratory and home study nights was random. The
frequency of respiratory events on the PSG was quantified using
indexes based on 2 definitions of hypopnea: the
respiratory disturbance index (RDI) using American Academy of
Sleep Medicine (AASM) Task Force criteria for
clinical research, and the Medicare guidelines. The PRDI and
oxygen desaturation index (PAT ODI) were then
evaluated against the polysomnography AASM guidelines (RDI.C)
and Medicare guidelines (RDI.M), respectively, for
both Watch-PAT100 diagnostic nights, yielding in-lab and home
comparisons. The setting for the PSGs was a sleep
laboratory affiliated with a tertiary-care academic medical
center. The PSG and PAT measures were compared using
the mean [2 SD] of the differences and the intra-class
correlation coefficient (ICC). The receiver-operator
characteristic
curve was used to assess optimum sensitivity and specificity and
calculate likelihood ratios. For the in-lab comparison,
there was high concordance between:
RDI.C and PAT RDI: ICC = 0.88, mean difference 2.5 [18.9] events
per hour
RDI.M and PAT ODI: ICC = 0.95, mean difference 1.4 [12.9] events
per hour
sleep time: ICC = 0.70, mean difference 7.0 [93.1] minutes
For the home-laboratory comparison, there was good concordance
between:
RDI.C and PAT RDI: ICC = 0.72, mean difference 1.4 [30.1] events
per hour
RDI.M and PAT ODI: ICC = 0.80, mean difference 1.6 [26.4] events
per hour
Home studies were performed with no technical failures. The
authors concluded in this study of a population of 30
35patients suspected of having OSA that the Watch-PAT100 can
quantify an ODI that compares very well with Medicare
criteria for defining respiratory events and an RDI that
compares favorably with AASM criteria for defining respiratory
Date: 6/4/2008, Page 13 of
events. They further believe that the device can be used with a
low failure rate for single use in the lab and home for
self-administered testing.
Zou et al. (2006) aimed at assessing the accuracy of a portable
monitoring device based on PAT to diagnose OSA
(OSA) and to propose a new standard for limited-channel device
validation using synchronized polysomnography
(PSG) home recordings in a population-based cohort, i.e. in a
population sample not preselected for OSA symptoms.
The 98 subjects (55 men; age, 60 ± 7 year; body mass index, 28 ±
4 kg/m2) from a community of 18,000 in Sweden
had single-night, unattended PSG and Watch-PAT100 in the home.
They were consecutively recruited from the
Swedish Skaraborg Hypertension and Diabetes Project. The
accuracy of Watch-PAT100 in RDI, AHI, ODI, and sleep-
wake detection was assessed by comparison with data from
simultaneous PSG recordings.
The mean PSG-AHI in this population was 25.5 ± 22.9 events per
hour. The Watch-PAT100 RDI, AHI, and ODI
correlated closely (0.88, 0.90, and 0.92; p < .0001,
respectively) with the corresponding indexes obtained by PSG.
The
areas under the curve for the receiver-operator characteristic
curves for Watch-PAT100 AHI and RDI were 0.93 and
0.90 for the PSG-AHI and RDI thresholds of 10 and 20 (p < .0001)
respectively. The agreement of the sleep-wake
assessment was 82 ± 7%. The authors concluded that the
Watch-PAT100 was reasonably accurate for unattended home
diagnosis of OSA in a population sample not preselected for OSA
symptoms. The authors propose that simultaneous
home PSG recordings in population-based cohorts is a reasonable
validation standard for assessment of simplified
recording tools for OSA diagnosis.
In Pillar et al. (2002), the authors state that arousals from
sleep are associated with increased sympathetic activation and
are therefore associated with peripheral vasoconstriction. The
authors hypothesized that digital vasoconstrictions as
measured by peripheral arterial tonometry (PAT), combined with
an increase in pulse rate, will accurately reflect
arousals from sleep and can provide an autonomic arousal index
(AAI). According to the authors, a previously studied
group of 40 sleep apnea patients simultaneously recorded by both
PSG and PAT systems generated an automated
algorithm using the PAT signal (and pulse rate derived from it)
was developed for detection of arousals from sleep.
This was further validated in this separate group of 96 subjects
which included 85 patients referred with suspected OSA
and 11 healthy volunteers. All subjects underwent a whole night
PSG with simultaneous PAT recording. The PSG
recordings were manually (blindly) analyzed for arousals based
on American Academy of Sleep Medicine (AASM)
criteria, while PAT was scored automatically. There was a
significant correlation between PSG and PAT arousals
(R=0.82, p<0.0001) with good agreement across a wide range of
values, and with a ROC curve having an area under
the curve (AUC) of 0.88. The authors conclude that automated
analysis of the peripheral arterial tonometry signal can
detect EEG arousals from sleep in a relatively quick and
reproducible fashion.
In Bar et al. (2003), the authors aimed at evaluating the
efficacy, reliability, and reproducibility of the Watch-PAT100
device for the diagnosis of OSAS as compared to in-laboratory,
standard PSG-based manual scoring. One hundred two
subjects (69 patients with OSAS and 33 normal non-consecutively
selected volunteers) underwent in-laboratory full
PSG simultaneously with Watch-PAT100 recording. Fourteen
subjects also underwent two additional unattended home
sleep studies with the Watch-PAT100 alone. The PSG recordings
were blindly scored for apnea/hypopnea according to
the American Academy of Sleep Medicine criteria (1999) and the
RDI [PSG-RDI] was calculated. The Watch-PAT100
data were analyzed automatically for the PAT RDI (PRDI) by a
proprietary algorithm that was the authors reported was
previously developed on an independent group of subjects. Across
a wide range of RDI levels, the PRDI was highly
correlated with the PSG-RDI (r = 0.88, p < 0.0001), with an area
under the receiver operating characteristic curve of
0.82 and 0.87 for thresholds of 10 events per hour and 20 events
per hour, respectively. The PRDI scores were also
highly reproducible, showing high correlation between home and
in-laboratory sleep studies (r =0.89, p < 0.001). The
authors concluded that the Watch-PAT100 may offer an accurate,
robust, and reliable ambulatory method for the
detection of OSAS with minimal patient discomfort.
Ayas et al. (2003) aimed at assessing the accuracy of a
wrist-worn device (Watch-PAT100) to diagnose OSA (OSA).
Thirty adult subjects (mean age was 47.0 ± 14.8 years, mean body
mass index 31.0 ± 7.6 kg/m2) were recruited
through advertisements and from a patient base of those with
suspected OSA to participate in this study. The study
included patients suspected of having sleep apnea and subjects
without suspected sleep apnea. The subjects had
simultaneous in-laboratory PSG and wore the Watch-PAT 100 during
a full-night recording. PSG sleep and respiratory
events were scored according to standard criteria. The mean PSG
AHI was 23 ± 23.9 events per hour and the mean
PAT AHI 23 ± 15.9 events per hour. There was a significant
correlation between the two (r = 0:87, p <0:001). To
assess sensitivity and specificity of Watch-PAT100, receiver
operator characteristic curves were constructed using a
variety of AHI threshold values (10, 15, 20, and 30 events per
hour). Optimal combinations of sensitivity and
specificity for the various thresholds were 82.6/71.4,
93.3/73.3, 90.9/84.2, and 83.3/91.7, respectively. The authors
concluded that the Watch-PAT100 is a device that can detect OSA
with reasonable accuracy and that it may be a useful
method to diagnose OSA.
In Pillar et al. (2003), the authors stated that they had
recently shown that automated analysis of in-lab recorded
35peripheral arterial tone (PAT) signal and the pulse rate
derived from it can accurately assess arousals from sleep as
Date: 6/4/2008, Page 14 of
defined by the American Academy of Sleep Medicine (AASM). In the
current study they aimed at extending these
findings to the Watch-PAT100. They recruited 68 subjects who
underwent a whole night PSG with simultaneous
recording of PAT signal by the ambulatory Watch-PAT100 device.
The PSG recordings were blindly scored via
manual analyzing for arousals based on AASM criteria, while PAT
was scored automatically based on the algorithm
developed previously. The authors determined that was a
significant correlation between AASM arousals derived from
the PSG and PAT autonomic arousals derived from the Watch-PAT100
(R=0.87, P<0.001), with consistency across a
wide range of values of AHI. The sensitivity and specificity of
PAT in detecting patients with at least 20 arousals per
hour of sleep were 0.80 and 0.79, respectively, with a receiver
operating characteristic curve having an area under the
curve of 0.87. They concluded that that automatic analysis of
peripheral arterial tonometry signal derived from the
ambulatory device Watch-PAT100 can accurately identify arousals
from sleep in a simple and time saving fashion
Diagnosis of OSA using CPAP
Senn et al. (2006) were one of a number of groups that studied
the feasibility of using CPAP to make a diagnosis of
OSA in patients with a high-pretest probability of disease.
Specifically, using a study of diagnostic accuracy in a
university sleep disorder setting, they wanted to evaluate
whether the diagnosis of OSA could be inferred from the
response to treatment with CPAP (CPAP trial); i.e. whether a
CPAP trial predict an AHI > 10 on PSG and how
successfully OSA patients were treated over a period of 4 or
more months. The accuracy of the CPAP trial would be
evaluated by comparing results to those of PSGs performed in all
patients (for validation) and by comparison to the
clinical outcomes of OSA patients after 4 months of treatment
with CPAP following a positive trial result. A trial by
CPAP was considered positive if, at the end of the followup
period, a patient reported using CPAP for 2 or more hours
per night and wanted to continue using CPAP. Baseline ESS
studies, quality of life measures (SF-36), a questionnaire
(Kump), as well as vigilance measures (OSLER test) (Bennett et
al. 1997; Jenkinson et al. 1999) were assessed in 76
sleepy snorers consecutively referred for a clinical diagnosis
of OSA. A diagnosis of OSA was defined as a mean AHI
> 10.
Of the original 195 consecutive patients referred for possible
participation in the study, after excluding patients not
meeting criteria, 76 patients (100% of those with AHI > 10
fitting criteria, average age 52) were enrolled in the study.
Forty-four of 76 patients (58%) had sleep apnea as confirmed by
an AHI > 10/h. The CPAP trial predicted sleep apnea
with a sensitivity of 80%, a specificity of 97%, and positive
and negative predictive values of 97% and 78%,
respectively. In 35 of 76 sleep apnea patients (46%) with
positive CPAP trial results, polysomnography could have
been avoided. These patients were prescribed long-term CPAP
therapy. After 4 months, 33 of 35 patients (94%) still
used CPAP and their symptoms remained improved. These patients
were identified by the CPAP trial with positive and
negative predictive values of 92% and 100%, respectively. The
authors concluded that CPAP is a "pragmatic" approach
to identify OSA patients with "CPAP-responsive disease" who
benefit from long-term CPAP therapy. They further
concluded that in a selected population, a trial of CPAP may
help to diagnose OSA, identify patients who benefit from
CPAP and reduce the need for polysomnography. Furthermore,
long-term CPAP therapy can be established without the
need for PSG.
Limitations of the study according to the authors included
patients designated as being "false positive" and exhibiting a
placebo effect from CPAP. Results may not be generalizable to
the Medicare population since by figures given in the
paper approximately one-sixth of the subjects were 65 years or
older.
Some proponents of CPAP have proposed that patients with high
pretest probability of diagnosis of OSA not undergo
PSG but proceed directly to CPAP titration either in the
laboratory or unattended with an autotitration device (Flemons
et al. 2003; Masa et al. 2004; Mulgrew et al. 2007 mentioned
above).
Fitzpatrick et al. (2003) reported similar outcomes between
standard laboratory-based CPAP titration and patient self-
titration in CPAP-naïve subjects. Eighteen CPAP-naive patients
(16 males, 50 ± 15 years old, apnea hypopnea index 40
± 20 with a new diagnosis of OSA) were tested. Testing was
performed before and after CPAP treatment in each of two
5-week study limbs. Compliance with CPAP treatment, the Sleep
Apnea Quality of Life Index, the Functional
Outcomes of Sleep Questionnaire score, ESS score, sleep
architecture, sleep apnea and maintenance of wakefulness
tests were measured. Both modes of CPAP treatment significantly
improved objective subjective measures of OSA, but
they did not differ in efficacy. The authors concluded that home
self-titration of CPAP is as effective as in-laboratory
manual titration in the management of patients with OSA.
Hukins (2005) also evaluated the use of low arbitrary pressure
CPAP before formal CPAP titration to determine if
arbitrary pressure CPAP is equivalent to formal CPAP in terms of
compliance and improvements in subjective
sleepiness and quality of life. Using an open-labeled,
randomized, parallel design, 93 subjects were randomized to
start
CPAP either after a CPAP titration sleep study (study-determined
pressure) or at an arbitrary pressure before the
treatment sleep study (arbitrary-pressure CPAP). Primary outcome
included ESS scores and secondary outcomes were
objective compliance, quality of life and the visual analog
(VAS) scale of subjective feelings towards CPAP therapy.
35The results of the study revealed that although there were no
differences in CPAP compliance, side effects, SF-36
parameters or ESS scores, there was significantly higher sleep
efficiency (proportion of sleep in the period potentially
Date: 6/4/2008, Page 15 of
filled by sleep- i.e. the ratio of total sleep time to time in
bed) in the arbitrary-pressure group compared to the study-
determined CPAP pressure group. The author also noted that
subjects who were unable to tolerate CPAP were
identified by the use of arbitrary pressure. This led to a
reduction in the proportion of "wasted" PSGs; i.e. studies
performed in subjects not persisting with treatment. According
to the author, a limitation of the study was the fact that
the results are not well generalizable to the Medicare
population since the average age in both groups was close to 50
years.
Other Diagnostic Strategies
Rice et al. (2006) piloted a study to evaluate unattended
cardiopulmonary (CP) sleep studies as a diagnostic and
treatment tool for patients with OSA. After all 106 subjects
were initially evaluated by a pulmonary physician to
identify those with a high risk of OSA, an ESS was administered.
Those who were felt to have a high suspicion of OSA
were offered either a PSG (which could take up to 6 months to
schedule), or an unattended CP sleep study. Patients
electing to use the unattended CP sleep study were lodged as
outpatients overnight in the medical center. The
diagnostic portable system used was the Embletta PDS, which
included an oral thermometer, a nasal flow sensor, a
snore microphone, a pulse oximeter, and strain gauges for
thoracic and abdominal expansion. AHI was the outcome of
interest. Patients with a positive CP test (an AHI of 5 events
per hour or greater) were sent home with a REMstar auto
CPAP system and a mask that was custom-fitted by a trained
respiratory therapist.
After using auto CPAP nightly for a week (REMstar auto CPAP
system adjusted to the patient’s pressure needs by
analyzing the shape curve of his/her airflow signal and peak
flow), patients were then issued a home CPAP machine
with settings based on the pressure that was found to be
effective for at least 90% of the trial patients. ESS scores
were
measured at baseline and after 6 months of home CPAP use.
Patients who had been prescribed home CPAP were
assessed for global sleepiness at 12 months. CP studies were
performed on 106 patients, all participants were males
(mean age 59.9±10.1), mean BMI of 33.5 and mean ESS score
(reference) of 13.1 ± 5.2. Of the 106 original patients,
auto CPAP was initiated on 92 subjects. Based on the results of
the one week auto CPAP, home CPAP was initiated on
84 patients. According to the authors, "among our patients,
improvement in OSA symptoms and long-term adherence
to prescribed CPAP was similar to published reports of patients
who had undergone conventional PSG testing." At 6
months follow-up, 98% of CPAP patients were available; ESS
scores at baseline and follow up were 14±4.6 and
10±5.6 (p=0.001), and adherence to CPAP usage was 84%.
Limitations of the study included the lack of confirmatory PSG
to determine rate of false positives (but the mean AHI
from this study was similar to that reported in published series
of patients who had PSGs; and the absolute magnitude
of ESS score improvement in this study was similar to that
reported for patients who were prescribed CPAP after a
PSG). Other limitations are the inability to calculate the
diagnostic accuracy of a negative CP study for OSA; the fact
that all subjects were male; and that adherence to prescribed
CPAP was not based on objective data but rather on self-
reporting.
CPAP Harms
A thorough review of the literature yielded almost no data on
any harm from CPAP. One German paper (Fietze et al.
1996) reported on 9 patients with an increase of central apneas.
Because of this complication, a rapid optimization of
the respiratory pressure or a change to nBiPAP (nasal bilevel
pressure support ventilation) therapy was necessary in
five of the patients. Two of the patients showed cardiac
arrhythmias, some of which were severe. One patient produced
a remarkable central hypoventilation during the initial phase of
CPAP-therapy. The nBiPAP-titration combined with
right-heart catheter monitoring could demonstrate in another
patient a possible cardiac decompensation through an
increased ventilatory pressure. The authors concluded that the
risk of positive-pressure ventilation is higher in patients
with accompanying cardiac, pulmonary, neuropsychiatric and/or
otorhinolaryngologic disorders. They suggested an
intensive "apparative" [sic] monitoring as well as staff
supervision during the introduction to a respiratory treatment
in
those patients. They believe that if complications from CPAP
appear, a rapid optimization of the ventilatory pressure or
a change to another respiratory treatment is indicated.
4. MedCAC
CMS convened the MedCAC on September 12, 2007 to consider
questions pertinent to this reconsideration. The
questions were appended to the proposed decision memorandum and
we refer the interested reader to that document.
We are not reiterating them here due to the length of this
document. Additional information about the meeting can be
found at:
https://www4.cms.hhs.gov/mcd/viewmcac.asp?where=index&mid=40.
The MedCAC expressed moderate to high confidence that there was
sufficient evidence to determine if clinical
evaluation combined with PSG can, in routine use, produce an
accurate diagnosis of OSA for the prescription of CPAP.
Moderate confidence was expressed on the evidence for clinical
evaluation combined with home sleep testing. Less
confidence was expressed on the evidence for clinical evaluation
used alone.
Considering the evidence on the ability of various diagnostic
strategies to correctly identify patients with OSA and
35exclude patients who do not have OSA, the MedCAC expressed the
following levels of confidence.
Clinical evaluation combined with PSG: strong moderate to high
Date: 6/4/2008, Page 16 of
Clinical evaluation combined with Type 2 home sleep testing:
strong moderate
Clinical evaluation combined with Type 3 home sleep testing:
moderate
Clinical evaluation combined with Type 4 home sleep testing:
less than moderate
Clinical evaluation alone: less than moderate
The MedCAC did not provide a formal consideration of home sleep
testing strategies that would employ clinical
evaluation in combination with an unclassified device, i.e. not
within Types 1-4.
The MedCAC decided not to address which clinical factors should
be included in the clinical evaluation.
Considering the evidence on the ability of various diagnostic
strategies to predict successful use of CPAP, the
MedCAC expressed moderately high confidence in clinical
evaluation combined with PSG; moderate confidence in
clinical evaluation combined with home sleep testing; low to
moderate confidence in clinical evaluation combined with
a trial of CPAP; and low confidence in clinical evaluation
alone.
The MedCAC expressed low to moderate confidence that the
strategy of a trial by CPAP would not produce clinically
meaningful harm. The concerns about potential harm relate to the
possibility of missing the diagnosis of non-OSA
pathology rather than concerns about CPAP itself.
The MedCAC expressed low to moderate confidence that its
conclusions could be generalized to the Medicare
population or to community based providers.
5. Evidenced based Guidelines
A November 14, 2007 search of
http://www.guidelines.gov/ produced several guidelines
relevant to CPAP or OSA in
adults. All had been published or updated since 2003. Portions
speaking to the questions posed in this memorandum
were excerpted and were included in the proposed decision
memorandum. We refer the reader to that document and
will not reiterate them here in consideration of the length of
this final decision memorandum. We note that the
American Academy of Sleep Medicine (AASM) revised its guidelines
while this NCA was open. We summarize that
revision below since it was not discussed in the proposed
decision memorandum.
American Academy of Sleep Medicine
Clinical guidelines for the use of unattended portable monitors
in the diagnosis of OSA in adult patients. Portable
Monitoring Task Force of the American Academy of Sleep Medicine.
Collop NA, Anderson WM, Boehlecke B,
Claman D, Goldberg R, Gottlieb DJ, Hudgel D, Sateia M, Schwab R;
Portable Monitoring Task Force of the American
Academy of Sleep Medicine. J Clin Sleep Med. 2007 Dec
15;3(7):737-47.
Based on a review of literature and consensus, the Portable
Monitoring Task Force of the American Academy of Sleep
Medicine (AASM) makes the following recommendations: unattended
portable monitoring (PM) for the diagnosis of
OSA (OSA) should be performed only in conjunction with a
comprehensive sleep evaluation. Clinical sleep evaluations
using PM must be supervised by a practitioner with board
certification in sleep medicine or an individual who fulfills
the eligibility criteria for the sleep medicine certification
examination. PM may be used as an alternative to
polysomnography (PSG) for the diagnosis of OSA in patients with
a high pretest probability of moderate to severe
OSA. PM is not appropriate for the diagnosis of OSA in patients
with significant comorbid medical conditions that may
degrade the accuracy of PM. PM is not appropriate for the
diagnostic evaluation of patients suspected of having
comorbid sleep disorders. PM is not appropriate for general
screening of asymptomatic populations. PM may be
indicated for the diagnosis of OSA in patients for whom
in-laboratory PSG is not possible by virtue of immobility,
safety, or critical illness. PM may also be indicated to monitor
the response to non-CPAP treatments for sleep apnea. At
a minimum, PM must record airflow, respiratory effort, and blood
oxygenation. The airflow, effort, and oximetric
biosensors conventionally used for in-laboratory PSG should be
used in PM. The Task Force recommends that PM
testing be performed under the auspices of an AASM-accredited
comprehensive sleep medicine program with written
policies and procedures. An experienced sleep
technologist/technician must apply the sensors or directly
educate
patients in sensor application. The PM device must allow for
display of raw data with the capability of manual scoring
or editing of automated scoring by a qualified sleep
technician/technologist. A board certified sleep specialist, or
an
individual who fulfills the eligibility criteria for the sleep
medicine certification examination, must review the raw data
from PM using scoring criteria consistent with current published
AASM standards. Under the conditions specified
above, PM may be used for unattended studies in the patient's
home. A follow-up visit to review test results should be
performed for all patients undergoing PM. Negative or
technically inadequate PM tests in patients with a high pretest
probability of moderate to severe OSA should prompt
in-laboratory polysomnography.
The AASM makes the following recommendations on the use of CPAP
with the level of recommendation in
parenthesis:
Standard - This is a generally accepted patient-care strategy,
which reflects a high degree of clinical certainty. The
term standard generally implies the use of Level I Evidence,
which directly addresses the clinical issue, or
overwhelming Level II Evidence.
Guideline - This is a patient-care strategy, which reflects a
moderate degree of clinical certainty. The term guideline
35implies the use of Level II Evidence or a consensus of Level
III Evidence.
Date: 6/4/2008, Page 17 of
Option - This is a patient-care strategy, which reflects
uncertain clinical use. The term option implies either
inconclusive or conflicting evidence or conflicting expert
opinion.
Treatment with continuous positive airway pressure (CPAP) must
be based on a prior diagnosis of OSA (OSA)
established using an acceptable method (Standard)
.
CPAP is indicated for the treatment of moderate to severe OSA
(Standard)
.
CPAP is recommended for the treatment of mild OSA (Option)
.
CPAP is indicated for improving self-reported sleepiness in
patients with OSA (Standard)
.
CPAP is recommended for improving quality of life in patients
with OSA (Option)
.
CPAP is recommended as an adjunctive therapy to lower blood
pressure in hypertensive patients with OSA (Option)
.
Full-night, attended polysomnography performed in the laboratory
is the preferred approach for titration to determine
optimal positive airway pressure; however, split-night,
diagnostic-titration studies are usually adequate (Guideline)
.
CPAP Usage should be objectively monitored to help assure
utilization (Standard)
.
Close follow-up for positive airway pressure (PAP) usage and
problems in patients with OSA by appropriately trained
health care providers is indicated to establish effective
utilization patterns and remediate problems, if needed. This is
especially important during the first few weeks of PAP use
(Standard)
.
The addition of heated humidification is indicated to improve
CPAP utilization (Standard)
.
The addition of a systematic educational program is indicated to
improve PAP utilization (Standard)
.
After initial CPAP setup, long-term follow-up for CPAP-treated
patients with OSA by appropriately trained health care
providers is indicated yearly and as needed to troubleshoot PAP
mask, machine, or usage problems (Option)
.
CPAP and bi-level positive airway pressure (BPAP) therapy are
safe; side effects and adverse events are mainly minor
and reversible (Standard)
.
While the literature mainly supports CPAP therapy, BPAP is an
optional therapy in some cases where high pressure is
needed and the patient experiences difficulty exhaling against a
fixed pressure or coexisting central hypoventilation is
present (Guideline)
.
BPAP may be useful in treating some forms of restrictive lung
disease or hypoventilation syndromes associated with
daytime hypercapnia (Option)
.
6. Professional Society Position Statements
American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS)
The AAO-HNS is the requestor of record for this reconsideration
and supports extension of Medicare coverage of OSA
diagnosis to portable HST devices.
The American Association for Respiratory Care (AARC)
The AARC recommends that CMS revise its coverage policy to
require sleep testing to be performed in accredited
facilities with accreditation to be determined by CMS. In
addition, AARC recommends that any new device introduced
into the home for sleep testing should meet minimum testing
criteria. For example, central apnea versus obstructive
apnea requires more physiologic data than pulse oximetry and
flow. AARC further recommended and suggested
language that CMS specify the types of personnel that are
qualified to provide home testing.
The American College of Chest Physicians (ACCP)
The ACCP concluded that additional research is needed addressing
clinical outcome in a variety of age and ethnic
populations that reflect society before this NCD can be revised.
The American Academy of Sleep Medicine (AASM)
The AASM requested that CMS not change its NCD on CPAP therapy
for OSA to allow diagnosis based on portable
monitoring. The AASM supports a modification of the two hour
rule based on expert opinion and not evidence.
7. Expert Opinion
CMS did not seek outside expert opinion beyond the TAs and the
MedCAC. However, many experts provided their
opinions as comments or position statements which are considered
in the relevant sections of this memorandum.
8. Public Comments
Initial comment period 3/14/2007 – 4/13/07
As noted above CMS uses the initial public comments to inform
its proposed decision. CMS responds in detail to the
public comments on a proposed decision when issuing the final
decision memorandum. CMS responses to initial
comments are, as customary, incorporated into our analysis.
CMS received a total of 717 comments during the initial public
comment period. Thirty-seven (5%) of the 717
comments were duplicates, resulting in 680 actual comments.
Commenters included organizations, manufacturers and
suppliers, physicians and other clinicians, and patients. One
hundred-seventy comments were generated by an industry-
sponsored write in campaign. Many stakeholders came in for
face-to-face meetings with CMS staff members and also
submitted formal comments. Fifty-seven percent (388/680) of the
commenters (including all 170 write-in comments)
35agreed with the requestor and supported expansion of Medicare
coverage to include the use of HST for the
identification of beneficiaries eligible for CPAP. Forty-three
percent (292/680) disagreed with the requestor.
Date: 6/4/2008, Page 18 of
Only 32 commenters expressed an interest in the trial use of
CPAP without a sleep study test. One commenter
recommended that the patient be allowed to have a trial period
on CPAP therapy for 2 to 3 days before allowing
Medicare coverage for CPAP therapy. Ten comments supported
revision of the requirement for 2 hours of recorded
sleep.
Many commenters questioned the motives of parties whose opinions
differed from their own. Specifically, some
commenters alleged that economic self-interest had led to
selective consideration of evidence in support of particular
opinions or guidelines.
Second comment period 12/14/2007-1/13/2008
CMS received a total of 300 timely public comments during the
second comment period. Most comments were not
accompanied by published scientific evidence. Listed below is a
summary of the comments received and CMS’
response:
Agrees with CMS proposed decision
Comment
Many commenters expressed support for all or parts of the
proposed decision. They noted that Medicare coverage of
home sleep studies to diagnose OSA to qualify for CPAP therapy
will improve access to care and that home sleep tests
are more accurate since you sleep more naturally in the home
setting.
Response
CMS appreciates the support for the proposed decision.
Disagrees with some or all of CMS’ proposed decision
Comment
Commenters questioned the integrity of the OSA treatment in the
community and cautioned those involved in the
decision making not to overlook the potential for abuse and not
to allow this technology to be unleashed until adequate
guidelines are available for appropriate utilization by
qualified physicians. Some commenters believe this policy
change will further degrade the current trend of inappropriate
CPAP titrations and poor compliance.
Response
We are aware that there is the potential for abuse with this
expansion of coverage, and we are taking steps to minimize
the vulnerability of the Medicare program. These safeguards may
include strategies beyond this NCD and rely on
separate authorities. We believe that the education requirements
for CPAP will support the appropriate provision of this
benefit. As we noted elsewhere in this document we believe that
CMS regulations require that diagnostic tests be
performed with an appropriate level of supervision. We recognize
that the polarization of the national stakeholder
community makes it difficult at the national level to
distinguish legitimate concerns from comments that may be
motivated entirely by financial or business considerations.
Medicare contractors may develop local strategies to ensure
that these services are only provided in a manner consistent
with the NCD and with applicable regulation.
Comment
Some commenters disagreed with the proposed coverage of the
Watch-PAT100 under the CED paradigm. They claim
that the Watch-PAT100 is a useful diagnostic tool and should not
be distinguished from other HST devices.
Response
We agree. CMS has in the final decision removed the CED
requirement for the use of the Watch-PAT100 HST device
for the purposes of this NCD. This is a three channel device and
we will treat it as a Type IV device under the NCD.
Comment
Some commenters note the risk of trying to identify and treat
OSA patients without a complete PSG, risk of missing
other diagnosis. Others questioned the use of HST in patients
with particular comorbidities such as Parkinson’s
Disease, chronic obstructive pulmonary disease (COPD) and
others. Some commenters support the use of HSTs for
those patients with a high pre test probability of OSA and no
evidence of other sleep disorders.
Response
As we discussed in the proposed decision, no test is perfect for
OSA diagnosis. It is important to note that we are not
requiring that HST be done in the place of PSG. If the
beneficiary’s treating physician has good reason to believe that
HST will be inadequate diagnostic tool for the beneficiary’s
condition, we expect that the physician would order a PSG
rather than HST. Similarly, if the beneficiary’s treating
physician has good reason to believe that the result of an HST
is
insufficient in light of the beneficiary’s clinical findings a
subsequent PSG could be performed. We emphasize here
that we expect that such retest decisions would be made on a
case by case basis and we are not suggesting that the
routine use of a two test routine would be reasonable and
necessary.
Comment
Some commenters addressed issues other than the provisions of
the proposed policy, for example the effect of past
CMS policies and the anticipated effect of this policy on their
business income.
35
Response
We appreciate that conditions in NCDs may have an impact on
various business entities. Still, under Section
Date: 6/4/2008, Page 19 of
1862(a)(1)(A) our primary focus is on the health care of
Medicare beneficiaries.
Comment
Some commenters claim that automatic sleep study scoring without
the ability to review, edit, and confirm validity of
raw data must not be allowed.
Response
The commenter did not submit any addition peer reviewed medical
literature to support this statement. Thus, we are not
making a determination on the use of automatic scoring in this
NCD. However, we remind the reader of CMS
regulations on diagnostic tests and the important role of the
treating physician and other practitioners under this benefit.
Comment
Several commenters made note of CMS instructions via materials
other than the NCD regarding sleep testing. In
October CMS ruled that patients must be monitored by a
registered polysomnographic technologist in sleep
laboratories. Some find it “amusing” that CMS ruled that
attended sleep studies could not be performed in a hotel or
motel setting starting 1/1/2008, yet considering unattended
studies for OSA in patients home.
Response
Entities that submit claims for Medicare payment may be subject
to operational requirements on staffing, physical
facilities or other factors. Thus, for example, a sleep
laboratory may have to meet Medicare requirements for laboratory
facilities. As the provisions in question are not part of this
NCD we will not address them in this memorandum.
Comment
Some commenters noted that some patients may have difficulty
performing the test at home without assistance.
Response
CMS agrees with this comment. We expect that the treating
physician will consider this possibility when
recommending HST rather than PSG.
Comment
A number of commenters suggest that the evidence is not
generalizable to the Medicare population and to nonspecialist
providers.
Response
While the generalizability of the evidence is less than perfect,
we do note that the MedCAC scoring on this issue was in
the low to moderate range, thereby indicating some confidence in
the generalizability of the evidence.
Comment
A commenter suggested that CPAP could help diagnose OSA
Response
We agree that there may be promise in this approach, but we have
determined that the evidence does not yet fully
support such use and we will only cover this use in the context
of CED.
Comment
Studies have not been evaluated in the pediatric population,
thus home studies should not be used in this population.
Response
Pediatric patients are, in general, not Medicare beneficiaries.
We remind the reader that the diagnostic requirements of
this policy are specific to adults.
Comment
Some commenters say that surgery will not necessarily correct
the sleep problem, and that this will entail more
diagnostic testing and possible more CPAP usage. They believe
that this will increase Medicare spending.
Response
CMS has deleted from this decision the requirement that surgery
be an alternative to the use of CPAP. While we
appreciate the commenters point, we will not speculate on the
effect of this NCD on the success or failure of surgical
treatment nor on the impact of the new NCD on future Medicare
spending..
Comment
HST should be considered for preliminary screening for OSA or
done away with all together.
Response
We believe that the evidence supports the use of most HST
diagnostic testing as alternatives to PSGs. We are not
providing coverage of preliminary screening tests for
beneficiaries in the absence of any signs or symptoms of OSA.
Coverage of purely screening tests (not diagnostic tests) are
established pursuant to specific legislation (e.g. screening
mammography, screening for glaucoma, etc.)
Partially Agrees with CMS’ decision
Comment
Some commenters asked us to narrow the scope on types of
allowable HST, generally to restrict the use of Type IV
35devices for the purposes of this NCD.
Response
Date: 6/4/2008, Page 20 of
CMS considered this comment in the development of the final
decision. We also note that the MedCAC expressed less
confidence about the evidence on the diagnostic usefulness of
Type IV HST than other types. Thus, we have provided
coverage for CPAP when the OSA is diagnosed via a Type IV device
only when the Type IV device measures three or
more channels.
Comment
Some commenters claim that compliance with the CPAP is largely
successful because of intervention from sleep
technicians being able to work with the patient.
Response
While we have not reviewed robust evidence speaking to the
specific value of the sleep technician in this regard, we are
not suggesting the opposite. We anticipate the providers
furnishing the HST will want to maximize the efficiency of
testing and minimize the occurrences of failed tests, i.e. tests
that are invalid due to faulty test technique. Thus we
anticipate that they will provide education to teach the
beneficiary to administer the HST and be available to assist the
patient with the HST.
Comment
Some commenters say that test equipment can come off and
patients will not recognize it. This would necessitate a
retest.
Response
During the initial clinical evaluation the patient’s treating
physician must assess whether the patient is capable of
successfully fulfilling his or her role in the completion of a
HST. An improperly performed test can be differentiated
from a test that was performed in a technically correct manner
but which is falsely positive or negative for other
reasons.
Comment
Some commenters claim that a12 week period of initial CPAP use
is not adequate to determine if the patient will use
and benefit from CPAP. Others proposed specific criteria to
determine use and benefit. The AASM proposes the use of
specific guidelines such as CPAP adherence for at least 4 hours
of sleep for at least 70% of the days or an improvement
in clinical symptoms. Other commenter’s recommend the use of
outcome measures to assess benefit.
Response
The evidence indicates that a 12 week period is sufficient for
this purpose. So long as they do not conflict with the
NCD, Medicare contractors may develop additional policies for
determining the necessary improvement in the
beneficiary’s OSA as a result of using CPAP.
Clarification requested on CMS’ decision
Comment
Some commenters asked whether IDTFs (Independent Diagnostic
Testing Facilities can provide HSTs.
Response
We are not making a specific determination about IDTFs in this
decision.
Comment
Some commenters asked what documentation will be required to
support claims for services provided in the context of
this NCD.
Response
We expect that the treating physician’s contemporaneous medical
record documentation will be adequate to describe
the beneficiary’s condition for services provided in the context
of OSA treatment. Medicare contractors may determine
what documentation may be required for their review of claims.
Comments with evidence
Comment
A number of comments with references to journal articles were
submitted.
Response
The majority reiterated data that we had considered or submitted
references on topics that were tangential to the scope
of our decision One commenter added references on CPAP harms
(Krieger et al 1983, Teschler et al. 1995, Piper et al.
1995) reiterating and reinforcing the little data we had on CPAP
harms. These data recommended taking special care
with CPAP use and treatment in patients with cardiopulmonary
disease. We believe that these data are consistent with
our proposed decision so we are not making any changes as a
result of this evidence.
VIII. CMS Analysis
NCDs are determinations by the Secretary with respect to whether
or not a particular item or service is covered
nationally under title XVIII of the Act. § 1869(f)(1)(B). In
order to be covered by Medicare, an item or service must
fall within one or more benefit categories contained within Part
A or Part B, must not be otherwise excluded from
35coverage. Moreover, with limited exceptions, the expenses
incurred for items and services must be “reasonable and
necessary” for the diagnosis or treatment of illness or injury
or to improve the functioning of a malformed body
Date: 6/4/2008, Page 21 of
member. § 1862(a)(1)(A)
.
In addition to section 1862(a)(1)(A) of the Act, a second
statutory provision may permit Medicare payment for items
and services in some circumstances. That statute, section
1862(a)(1)(E) of the Act, provides, in pertinent part, that:
(a) Notwithstanding any other provision of this title, no
payment may be made under part A or part B for any expenses
incurred for items or services—
. .
.
(E) in the case of research conducted pursuant to section 1142,
which is not reasonable and necessary to carry out the
purposes of that section[.
]
. .
.
Section 1142 of the Act describes the authority of the AHRQ. CMS
has described this statute more fully in a Guidance
Document available at
https://www.cms.hhs.gov/ncpc_view_document.asp?id=8. See
also section 310 Medicare NCD
Manual.
Under the authority of section 1862(a)(1)(E) of the Act, CMS may
pay for items and services furnished in connection
with certain medical research. Coverage is conditioned on care
being delivered in a setting with a pre-specified data
collection process and additional protections in place such as
are present in some research studies. Under section 1142
of the Act, research may be conducted on the outcomes,
effectiveness, and appropriateness of health care services and
procedures to identify the manner in which diseases, disorders,
and other health conditions can be prevented,
diagnosed, treated, and managed clinically. In addition,
evaluations of the comparative effects, health and functional
capacity; alternative services and procedures utilized in
preventing, diagnosing, treating, and clinically managing
diseases, disorders, and other health conditions may be
conducted.
In rare instances, for some items or services, CMS may determine
that the evidence is very preliminary and not
reasonable and necessary for Medicare coverage under section
1862(a)(1)(A) of the Act, but, if the following criteria
are met, coverage with study participation might be appropriate:
a. The evidence includes assurance of basic safety;
b. The item or service has a high potential to provide
significant benefit to Medicare beneficiaries; and
c. There are significant barriers to conducting clinical trials.
These research studies will be rigorously designed and include
additional protections and safety measures for
beneficiaries.
To qualify for reimbursement, such a study must be designed to
produce evidence that could be used in a future NCD
that would focus on whether the item or service should be
covered by Medicare under 1862(a)(1)(A) of the Act.
Payment for the items and services provided in the study will be
restricted to the Medicare qualified patients involved
as human subjects in the study.
Consistent with section 1142 of the Act, AHRQ supports clinical
research studies that CMS determines meet the above-
listed standards and address the above-listed research
questions.
REVIEW OF THE EVIDENCE
A number of issues have emerged during our review of the
evidence. Some physicians express concern about the lack
of timely access to PSGs while others argue that access is not
problematic; stakeholders debate the comparable
accuracy of home apnea monitoring and PSGs; and recent research
suggests that neither PSG nor HST may be needed
for the diagnosis of CPAP-responsive OSA in selected patient
populations. Paradoxically, some patients’ OSA
symptoms may be so severe that they cannot sleep for a
sufficient continuous duration to complete a PSG. Adding to
the complexity of our review, the stakeholder community itself
is clearly polarized into opposing camps.
The relevance of OSA diagnosis is founded on the long term
morbidity and mortality that have been observed in
patients who display a particular constellation of symptoms,
signs and test results. Absent that morbidity and mortality,
a self-limited apneic episode in and of itself appears of little
consequence. Hence the challenge is to select for long term
CPAP treatment only those patients who will benefit from OSA
therapy, against a background of persons who may for
various reasons have a normal or abnormal test on a given night.
It is important to state at the outset that sleep testing,
whether via PSG or HST, is used to confirm or refute a clinical
suspicion of OSA. In other words, we have no evidence that
physicians refer "normal" patients, i.e. patients who
manifest no symptoms or signs of OSA, for sleep testing. Sleep
testing does not occur in a vacuum, divorced from the
overall clinical evaluation. We also note that while this NCD
speaks to the diagnosis of OSA in the context of Medicare
coverage of CPAP devices, we are not establishing coverage
criteria for the diagnosis of OSA for other purposes, such
as the coverage of other OSA treatments. Nor are we addressing
the use of sleep testing to diagnose conditions other
than OSA. Hence the accurate identification of Medicare
beneficiaries who will respond clinically to CPAP is at the
35heart of this review and analysis.
Date: 6/4/2008, Page 22 of
PSG is utilized as a reference standard in many clinical trials;
however, we do not believe it is a true gold standard. In a
circular argument, the test result has been incorporated into
the diagnosis of the disease itself. In the absence of a
pathologic gold standard, this is an understandable though not
ideal concession to practicality. The accuracy and
precision of PSG may be compromised by many factors such as
inter-reader variability, the use of different test
instruments, night to night variability in a given patient, and
patient ability to sleep in a non-home setting. Even if all
these variables are controlled, the PSG test itself has not been
proven to identify all true cases of OSA, i.e. those
persons who will develop OSA-associated morbidity and mortality
if untreated.
Therefore, when PSG is performed and read with a threshold of
AHI > 15 events per hour for OSA, the sensitivity for
detecting a true case of OSA is not known. Neither is its
specificity for detecting those who do not have OSA truly
known. An AHI suggestive of OSAHS does not conclusively identify
those patients who will benefit from treatment.
Since the true sensitivity and specificity of PSG are uncertain
and the reported agreement between HST and PSG is not
complete, we are concerned that a significant number of true
cases of OSA are not detected by either test. We are also
faced with evidence that some patients who test positive for OSA
do not appear to respond appropriately to CPAP
therapy, in some cases due to poor compliance with CPAP use.
Question 1: Is the evidence adequate to determine that
diagnostic strategies other than facility based PSG accurately
identify patients with OSA who will benefit from CPAP treatment?
We note evidence from our internal assessment and from the AHRQ
TAs that HST devices may, with high positive
likelihood ratios (> 10) and low negative likelihood ratios (<
0.1), identify patients who have AHIs suggestive of
OSAHS. Although there is published data comparing HST with PSG,
in the absence of a true gold standard it is
challenging to categorize the discrepancies as errors.
The body of evidence pertinent to the use of HST devices for the
diagnosis of OSA is significantly more robust than
when we last considered this NCD. This is supported by the more
favorable September 2007 MedCAC scores for HST
compared to the September 2004 MCAC scores. Thus, we find that
the evidence is sufficient to conclude that, in
appropriately selected patients, some HST monitors will identify
a significant proportion of patients with OSA who
will respond clinically to CPAP and will exclude a significant
proportion of those who will not.
CMS also reviewed oximetry alone for the diagnosis of sleep
apnea. There was limited evidence and many of the
authors recognized limitations of the studies. We believe the
evidence reviewed does not demonstrate its utility in the
diagnosis of OSA, and we cannot be confident that this
diagnostic modality accurately identifies those patients with
OSA who will respond clinically to CPAP and excludes those who
will not.
The TA analyzed Type IV monitors with three or more channels
separately from those with only one or two channels.
The quality of the evidence on the former is described as higher
than on the latter. We also note that the TA did not
include all Type IV monitors.
“…However, especially for type IV devices, we excluded the few
studies that did not measure directly at least one
respiratory signal or the O2 saturation. Thus, studies using
only static charge-sensitive mattresses, only Holter
recordings for heart rate, or studies that used only analysis of
snoring sounds were excluded. Similarly, we excluded
studies that that used pulse oximetry but analyzed only the
variability of the heart rate (i.e., used oximetry in lieu of
ECG to detect pulse rate) and did not evaluate O2 saturation
patterns. In general, monitors that did not record a
respiratory signal or SaO2 during sleep rely on “indirect”
assessment of respiratory disturbances in people suspected
for OSAHS, and most often were described in older studies. The
frequency of respiratory disturbances is a key issue in
the diagnosis of OSAHS, and is assessed by the vast majority of
modern monitors.”
In light of the lack of evidence of utility for oximetry and its
classification as a Type IV device, as well as the TA
finding of greater diagnostic accuracy in Type IV monitors with
three or more channels, we have reevaluated our
proposed conclusion to cover CPAP based on OSA diagnosis via
Type IV devices as a group. We believe our evidence
review demonstrates that single channel devices, such as
oximetry, are not adequate to identify appropriate candidates
for CPAP. Thus, we are modifying our proposed decision and will,
with regards to the use of Type IV HST for the
diagnosis of OSA, only cover CPAP when the diagnosis of OSA
includes a positive test with Type IV device
measuring at least three channels.
CMS separately reviewed evidence on the use of the Watch-PAT100
device (see above), a multichannel device that
measures PAT. The conclusions that can be confidently drawn from
the evidence, while mildly constrained by
methodologic limitations (sample and subject selection, sample
size, non-consecutivity of subjects, confounders not
accounted for, and combining results of different types of
patients in analysis), are of similar strength as that available
for many of the type IV devices in the TA and, therefore, we
consider the Watch-PAT100 as a three channel Type IV
device for the purposes of this decision.
Even though the evidence we reviewed was not adequate to support
oximetry testing alone under § 1862(a)(1)(A),
some of the evidence does suggest a benefit. Thus, we have
determined to cover CPAP for beneficiaries with the
35diagnosis of OSA based on the results of a diagnostic
procedure other than PSG or Type II, Type III, or Type IV
measuring at least three channels for HST only in the context of
a clinical study that meets the criteria approved by
Date: 6/4/2008, Page 23 of
AHRQ and reported at #6 of this decision.
Even though we believe the evidence supports using PSG or HST
for diagnosis of OSA, the evidence also demonstrates
that many patients with a positive PSG or HST do not benefit
from CPAP. We do, however, have evidence from an
RCT (Mulgrew 2007) that a trial period of up to 12 weeks of CPAP
after the initial diagnosis is beneficial in
identifying those beneficiaries who positively respond to CPAP.
The evidence indicates that patients who do not have
true OSA (false positives) will quickly reject CPAP treatment in
practice and will not be harmed by a short exposure to
CPAP. Moreover, in our final decision we are only providing
coverage of CPAP beyond twelve weeks for those
beneficiaries that have a positive clinical response to CPAP.
Question 2: Is the evidence adequate to determine that the
accurate diagnosis of OSA requires at least two hours
continuous recorded sleep?
We could find no rigorous evidence associating diagnostic
accuracy with continuous sleep time recording of at least
two hours duration. We are also confronted with reasonable
arguments that patients with the most severe OSA are in
practice incapable of continuous sleep of two hours duration.
Therefore, we have determined that the answer to
Question 2 is no. However, the current standards of requiring a
rate of > 15 events/hour over two hours for less
symptomatic patients and 5 through 14 events/hour over two hours
for more symptomatic patients do require a
minimum number of events. For example, a patient who has at
least 15 recorded events per hour over a two hour period
would have had at least 30 recorded events. Thus, while we no
longer believe two continuous hours of recorded sleep
are always necessary, we will continue to require that the total
number of events needed for a positive test to be that
which would need to occur over two hours to arrive at the
specified rates in the current NCD. That is, recording of at
least 30 events for patients without comorbidities and at least
10 events for patients with comorbidities is required for
the computation of events per hour. The effect of this change is
to permit coverage of CPAP in those beneficiaries
whose OSA was paradoxically too severe to permit successful
completion of the test under the previous NCD without
removing coverage for beneficiaries who would have met the
requirements of the previous NCD.
Question 3: Is diagnosis of OSA by clinical criteria alone
sufficient for the use of CPAP in the absence of either a
positive PSG or a positive unattended multichannel HST?
The published literature on both PSG and HST for OSA diagnosis
reflects the results of clinical studies enrolling
subjects referred by a medical provider for a test based on
clinical suspicion of OSA. Those providers likely made the
referral because the subject presented with one or more symptoms
or signs such as snoring, daytime sleepiness,
witnessed apneic episodes, a thick neck, a higher BMI, or a
positive sleep questionnaire, to mention some possibilities.
If a patient with clinically suspected OSA undergoes PSG or HST,
the patient is referred for CPAP if the PSG is
positive. The evidence indicates that both of these strategies
result in an unknown number of false positive and false
negative diagnoses.
There is evidence, albeit limited, to support the use of CPAP in
lieu of PSG or HST in the diagnosis of OSA. This is
based on the observation that patients with OSA are more
tolerant of CPAP than patients who do not possess this
condition, and that the use of CPAP does not result in untoward
effects even in patients who do not have a diagnosis of
OSA. The MedCAC expressed little confidence in the evidence
currently available to support this use. We do not
believe that this evidence is currently sufficient to definitely
answer this question and we therefore have determined
that the answer to Question 3 is no.
However, though the evidence we reviewed was not adequate to
support coverage of CPAP under § 1862(a)(1)(A)
based on a clinical evaluation alone for the diagnosis of OSA,
some of the evidence does suggest a benefit. Thus, we
will cover a clinical evaluation without sleep testing for the
diagnosis of OSA in the context of a clinical study that
meets the AHRQ criteria outlined at #6 of this decision.
Harms of CPAP
We found little evidence of harm attributable to CPAP. We
recognize that the population that currently undergoes
CPAP is somewhat narrower than all clinically suspected cases
and that the generalizability of the current literature on
harm may be poorly generalizable to populations beyond those
that currently qualify for CPAP. Further, persons with
co-morbidities associated with OSA may be at more risk than
suspected. However there is limited evidence on this
topic and thus we cannot confidently conclude that significant
possible harm has in fact been excluded. In other words,
the absence of evidence of harm does not reliably exclude the
likelihood of harm if a methodologically rigorous
assessment for harm has not been completed. Our concerns are
shared by the MedCAC, which expressed low to
moderate confidence that the strategy of a trial by CPAP would
not produce clinically meaningful harm. Potential
concerns about potential harm include the possibility of missing
the diagnosis of non-OSA pathology in addition to
concerns about potential harms attributable to CPAP itself
Summary
We have determined that the evidence is adequate to conclude
that CPAP is reasonable and necessary under section
351862(a)(1)(A) of the Act for adult beneficiaries with OSA
diagnosed by a clinical examination accompanied by a
positive PSG, Type II HST, Type III HST or a Type IV HST
measuring three of more channels. We are considering
Date: 6/4/2008, Page 24 of
Watch-PAT 100 as a three channel Type IV device for the purposes
of this decision. Since we have evidence that not
all patients with a positive PSG or HST will benefit from CPAP,
we are determining that CPAP is initially only
reasonable and necessary for a period of 12 weeks to determine
benefit from and compliance with this therapy.
Coverage beyond that period is contingent on the beneficiary’s
OSA improving as a result of CPAP.
As we have not found rigorous evidence to support continuing the
requirement for a minimum of two hours of
continuous recorded sleep time, we have removed that
requirement. We appreciate the supportive public comments on
this point.
We are also deleting the language in the past NCD that required
documentation of "moderate to severe OSA" and
"surgery is a likely alternative" as a condition of CPAP
coverage. We believe that they are no longer needed as stand
alone requirements since we have outlined in very specific terms
the requirements for a positive diagnosis.
We acknowledge the concerns that some of these patients who do
not tolerate CPAP may have other conditions for
which PSG or other testing may be indicated and we anticipate
that a prudent physician would refer the patient for such
testing if needed.
The evidence indicates that some risk factors for OSA are
modifiable over time; for example, a patient may gain or lose
weight, or resume or discontinue tobacco smoking. This raises
two specific concerns. One, patients who initially have a
true negative test may, years later, progress to more severe
disease and may subsequently truly test positive. Second,
patients who initially require CPAP may modify their underlying
risk factors for OSA and improve to the point that
further CPAP treatment is not required. We believe that these
determinations are best made at this time by local
Medicare contractors who can consider the medical information of
the individual patient.
In general, CMS regulation at 42 CFR 410.32(a) requires that all
diagnostic tests “…must be ordered by the physician
who is treating the beneficiary, that is, the physician who
furnishes a consultation or treats a beneficiary for a specific
medical problem and who uses the results in the management of
the beneficiary’s specific medical problem. Tests not
ordered by the physician who is treating the beneficiary are not
reasonable and necessary...” There are some specific
exceptions specified in the regulations.
For the purposes of this NCD on CPAP, we expect that the
beneficiary’s treating physician will assess the beneficiary
and, if a reasonable suspicion of sleep apnea is indicated by
those clinical findings, order appropriate sleep testing and
use the results in the management of the beneficiary’s condition
to make or exclude a diagnosis of OSA. The initiation
of home sleep testing or evaluation of the test results without
a prior order from the beneficiary’s treating physician
would not be considered sufficient for the coverage of CPAP.
We recognize that diagnostic sleep testing is also used to aid
the management of other conditions, e.g. narcolepsy and
nocturnal seizures. This NCD does not speak to the
characteristics of sleep testing to qualify Medicare
beneficiaries for
treatments other than CPAP for OSA.
As we discussed earlier in the decision memorandum, OSA has a
spectrum of severity. Individual patients vary in their
response to and adherence with CPAP treatment. Thus, the
management of the beneficiary’s specific medical problem,
in this instance OSA, does not end with the initiation of CPAP
treatment, and we expect that the beneficiary’s response
and adherence would be reflected in the contemporaneous medical
record and adequate documentation will be
available to support claims for Medicare payment.
CMS regulation at 42 CFR 410.32(b)(1) requires that diagnostic
tests “…covered under section 1861(s)(3) of the Act
and payable under the physician fee schedule must be furnished
under the appropriate level of supervision by a
physician as defined in section 1861(r) of the Act. Services
furnished without the required level of supervision are not
reasonable and necessary…” In the case of HST this is general
supervision. Thus we expect that PSG and HST will be
furnished with the appropriate level of supervision and we
believe that local Medicare contractors may develop and
implement local policies to ensure that claims are appropriately
paid.
We remind the reader that suppliers of CPAP devices to Medicare
beneficiaries are subject to regulatory requirements
in addition to the coverage conditions of this NCD and that
these requirements apply to physicians who supply DME.
We note the following language as an example (72 FR 51019-51020
(9/5/07):
Response: In Phase II, we stated that the definition of
"referral" excludes services personally performed or provided
by the referring physician, but specifically includes any
services performed or provided by anyone else (69 FR 16063).
This interpretation is codified in the definition of "referral"
at § 411.351. It is possible for a physician to order and
personally furnish antigens to a patient and to order a refill
for, and personally refill, an implantable pump. In such
instances, there would be no "referral" for a designated health
service, and no exception is needed.
We note that the furnishing of durable medical equipment (DME)
and supplies by a referring physician requires a
different analysis than the mere refilling of an implantable
pump. There are few, if any, situations in which a referring
physician would personally furnish DME and supplies to a
patient, because doing so would require that the physician
himself or herself be enrolled in Medicare as a DME supplier and
personally perform all of the duties of a supplier as
35set forth in the supplier standards in § 424.57(c).
Date: 6/4/2008, Page 25 of
DME suppliers are entities that provide services under the
specific Part B benefit for the provision of medical
equipment and supplies for use in the patient's home. These
entities must be enrolled with the appropriate Medicare
contractor as a DME supplier and must meet all of the
professional supplier standards and quality standards that we
require through regulations and administrative or program
instructions. The enrollment requirements and professional
supplier standards are not waived in those situations in which a
physician furnishes DME directly to the patient. The
services to be personally performed by the physician would
include, but not be limited to, the following, as appropriate
•
•
Personally fit the item for the beneficiary;
•
Provide necessary information and instructions concerning use of
the DME;
•
Advise the beneficiary that he or she may either rent or
purchase inexpensive or routinely purchased DME;
•
Explain the purchase option for capped rental DME;
•
Explain all warranties;
•
(Usually) deliver the DME to the beneficiary at home; and
•
Explain to the beneficiary at the time of delivery how to
contact the physician in his or her capacity as a DME
supplier by telephone.
A referring physician claiming to provide DME personally would
need to maintain adequate documentation to
establish that the physician personally performed these and
other required DME supplier activities. All of these supplier
requirements would need to be satisfied in order for a physician
to be considered to be providing personally DME items
and supplies. This is true for all DME furnished by a physician,
including, for example, continuous positive airway
pressure (CPAP) equipment. We believe that it is highly unlikely
that a referring physician would meet the criteria for
personally performed services when dispensing CPAP or other DME
equipment. Thus, the dispensing of CPAP
equipment by a physician would almost always constitute a
"referral" for purposes of the physician self-referral statute,
as would the dispensing of CPAP equipment by anyone else
affiliated with the referring physician, such as a nurse or
physician assistant. We note that CPAP equipment is DME that
does not qualify for the in-office ancillary services
exception.
Finally, while we have not found adequate evidence to determine
that CPAP is reasonable and necessary under §
1862(a)(1)(A) in beneficiaries who have a clinical diagnosis of
OSA but have not had a positive PSG or a Type II, III,
or IV (measuring three or more channels) HST , there is some
evidence that suggests that other diagnostic tests or a
clinical diagnosis alone may improve outcomes. Thus, we have
determined that CPAP is covered in beneficiaries who
have a clinical diagnosis of OSA but have not had a PSG or a
Type II, Type III, or CMS recognized Type IV HST only
when provided in a clinical study that meets the AHRQ
requirements originally set forth in the proposed decision and
finalized here at #6.
X. Conclusion
We received a request to reconsider the 2005 NCD for CPAP
Therapy for OSA (CAG-00093R) to allow coverage of
CPAP based upon a diagnosis of OSA by HST. After considering
public comments and additional information, we are
making the following changes to the NCD for CPAP. The revised
indications and limitations NCD are noted in
Appendix B.
1.
Coverage of CPAP is initially limited to a 12 week period for
beneficiaries diagnosed with OSA as
subsequently described. CPAP is subsequently covered for those
beneficiaries diagnosed with OSA whose OSA
improved as a result of CPAP during this 12 week period.
We remind the reader that DMEPOS suppliers are required to
provide beneficiaries with necessary information
and instructions on how to use Medicare-covered items safely and
effectively. 42 CFR 424.57(c)(12). Failure to
meet this standard may result in revocation of the DMEPOS
supplier’s billing privileges. 42 CFR 424.57(d).
2.
CPAP for adults is covered when diagnosed using a clinical
evaluation and a positive:
a.
polysomnography (PSG) performed in a sleep laboratory; or
b.
unattended home sleep monitoring device of Type II; or
c.
unattended home sleep monitoring device of Type III; or
d.
unattended home sleep monitoring device of Type IV, measuring at
least three channels
We remind the reader that, in general, pursuant to 42 CFR
410.32(a) diagnostic tests that are not ordered by the
beneficiary’s treating physician are not considered reasonable
and necessary. Pursuant to 42 CFR 410.32(b)
35diagnostic tests payable under the physician fee schedule that
are furnished without the required level of
supervision by a physician are not reasonable and necessary.
Date: 6/4/2008, Page 26 of
3.
A positive test for OSA is established if either of the
following criterion using the Apnea-Hypopnea Index
(AHI) or Respiratory Disturbance Index (RDI) are met:
.
AHI or RDI greater than or equal to 15 events per hour, or
.
AHI or RDI greater than or equal to 5 and less than or equal to
14 events per hour with documented
symptoms of excessive daytime sleepiness, impaired cognition,
mood disorders or insomnia, or
documented hypertension, ischemic heart disease, or history of
stroke.
The AHI is equal to the average number of episodes of apnea and
hypopnea per hour. The RDI is equal to the
average number of respiratory disturbances per hour.
4.
If the AHI or RDI is calculated based on less than two hours of
continuous recorded sleep, the total number of
recorded events to calculate the AHI or RDI during sleep testing
is at least the number of events that would
have been required in a two hour period.
5.
We are deleting the distinct requirements that an individual
have moderate to severe OSA and that surgery is a
likely alternative.
6.
CPAP based on clinical diagnosis alone or using a diagnostic
procedure other than PSG or Type II, Type III, or
a Type IV HST measuring at least three channels is covered only
when provided in the context of a clinical
study when that study meets the following standards:
A clinical study seeking Medicare payment for CPAP provided to
the beneficiary pursuant to Coverage with
Evidence Development (CED) must address one or more of the
following questions:
Date: 6/4/2008, Page 27 of
35
a. In Medicare aged subjects with clinically identified risk
factors for OSA, how does the diagnostic
accuracy of a clinical trial of CPAP compare with PSG and Type
II, III & IV HST in identifying
subjects with OSA who will respond to CPAP?
b. In Medicare aged subjects with clinically identified risk
factors for OSA who have not undergone
confirmatory testing with PSG or Type II, III & IV HST, does
CPAP cause clinically meaningful harm?
The study must meet the following additional standards:
c. The principal purpose of the research study is to test
whether a particular intervention potentially
improves the participants’ health outcomes.
d. The research study is well-supported by available scientific
and medical information or it is intended to
clarify or establish the health outcomes of interventions
already in common clinical use.
e. The research study does not unjustifiably duplicate existing
studies.
f. The research study design is appropriate to answer the
research question being asked in the study.
g. The research study is sponsored by an organization or
individual capable of executing the proposed
study successfully.
h. The research study is in compliance with all applicable
Federal regulations concerning the protection of
human subjects found at 45 CFR Part 46. If a study is
FDA-regulated, it also must be in compliance with
21 CFR Parts 50 and 56.
i. All aspects of the research study are conducted according to
the appropriate standards of scientific
integrity.
j. The research study has a written protocol that clearly
addresses, or incorporates by reference, the
Medicare standards.
k. The clinical research study is not designed to exclusively
test toxicity or disease pathophysiology in
healthy individuals. Trials of all medical technologies
measuring therapeutic outcomes as one of the
objectives meet this standard only if the disease or condition
being studied is life-threatening as defined
in 21 CFR § 312.81(a) and the patient has no other viable
treatment options.
l. The clinical research study is registered on the
ClinicalTrials.gov website by the principal
sponsor/investigator prior to the enrollment of the first study
subject.
m. The research study protocol specifies the method and timing
of public release of all pre-specified
outcomes to be measured including release of outcomes if
outcomes are negative or study is terminated
early. The results must be made public within 24 months of the
end of data collection. If a report is
planned to be published in a peer-reviewed journal, then that
initial release may be an abstract that meets
the requirements of the International Committee of Medical
Journal Editors. However, a full report of
the outcomes must be made public no later than three (3) years
after the end of data collection.
n. The research study protocol must explicitly discuss
subpopulations affected by the treatment under
investigation, particularly traditionally underrepresented
groups in clinical studies, how the inclusion
and exclusion criteria affect enrollment of these populations,
and a plan for the retention and reporting
of said populations on the trial. If the inclusion and exclusion
criteria are expected to have a negative
effect on the recruitment or retention of underrepresented
populations, the protocol must discuss why
these criteria are necessary.
o. The research study protocol explicitly discusses how the
results are or are not expected to be
generalizable to the Medicare population to infer whether
Medicare patients may benefit from the
intervention. Separate discussions in the protocol may be
necessary for populations eligible for Medicare
due to age, disability or Medicaid eligibility.
Consistent with section 1142 of the Act, AHRQ supports clinical
research studies that CMS determines
meet the above-listed standards and address the above-listed
research questions
APPENDIX A
General Methodological Principles of Study Design
(Section VI of the Decision Memorandum)
When making NCDs, CMS evaluates relevant clinical evidence to
determine whether or not the evidence is of
sufficient quality to support a finding that an item or service
is reasonable and necessary. The overall objective for the
35critical appraisal of the evidence is to determine to what
degree we are confident that: 1) the specific assessment
questions can be answered conclusively; and 2) the intervention
will improve health outcomes for patients.
Date: 6/4/2008, Page 28 of
We divide the assessment of clinical evidence into three stages:
1) the quality of the individual studies; 2) the
generalizability of findings from individual studies to the
Medicare population; and 3) overarching conclusions that can
be drawn from the body of the evidence on the direction and
magnitude of the intervention’s potential risks and
benefits.
The methodological principles described below represent a broad
discussion of the issues we consider when reviewing
clinical evidence. However, it should be noted that each
coverage determination has its unique methodological aspects.
Assessing Individual Studies
Methodologists have developed criteria to determine weaknesses
and strengths of clinical research. Strength of
evidence generally refers to: 1) the scientific validity
underlying study findings regarding causal relationships between
health care interventions and health outcomes; and 2) the
reduction of bias. In general, some of the methodological
attributes associated with stronger evidence include those
listed below:
•
Use of randomization (allocation of patients to either
intervention or control group) in order to minimize bias.
•
Use of contemporaneous control groups (rather than historical
controls) in order to ensure comparability
between the intervention and control groups.
•
Prospective (rather than retrospective) studies to ensure a more
thorough and systematical assessment of factors
related to outcomes.
•
Larger sample sizes in studies to demonstrate both statistically
significant as well as clinically significant
outcomes that can be extrapolated to the Medicare population.
Sample size should be large enough to make
chance an unlikely explanation for what was found.
•
Masking (blinding) to ensure patients and investigators do not
know to which group patients were assigned
(intervention or control). This is important especially in
subjective outcomes, such as pain or quality of life,
where enthusiasm and psychological factors may lead to an
improved perceived outcome by either the patient or
assessor.
Regardless of whether the design of a study is a randomized
controlled trial, a non-randomized controlled trial, a cohort
study or a case-control study, the primary criterion for
methodological strength or quality is the extent to which
differences between intervention and control groups can be
attributed to the intervention studied. This is known as
internal validity. Various types of bias can undermine internal
validity. These include:
•
Different characteristics between patients participating and
those theoretically eligible for study but not
participating (selection bias)
.
•
Co-interventions or provision of care apart from the
intervention under evaluation (performance bias).
•
Differential assessment of outcome (detection bias).
•
Occurrence and reporting of patients who do not complete the
study (attrition bias).
In principle, rankings of research design have been based on the
ability of each study design category to minimize these
biases. A randomized controlled trial minimizes systematic bias
(in theory) by selecting a sample of participants from a
particular population and allocating them randomly to the
intervention and control groups. Thus, in general,
randomized controlled studies have been typically assigned the
greatest strength, followed by non-randomized clinical
trials and controlled observational studies. The design, conduct
and analysis of trials are important factors as well. For
example, a well designed and conducted observational study with
a large sample size may provide stronger evidence
than a poorly designed and conducted randomized controlled trial
with a small sample size. The following is a
representative list of study designs (some of which have
alternative names) ranked from most to least methodologically
rigorous in their potential ability to minimize systematic bias:
Randomized controlled trials
Non-randomized controlled trials
Prospective cohort studies
Retrospective case control studies
Cross-sectional studies
Surveillance studies (e.g., using registries or surveys)
Consecutive case series
Single case reports
When there are merely associations but not causal relationships
between a study’s variables and outcomes, it is
35important not to draw causal inferences. Confounding refers to
independent variables that systematically vary with the
causal variable. This distorts measurement of the outcome of
interest because its effect size is mixed with the effects of
Date: 6/4/2008, Page 29 of
other extraneous factors. For observational, and in some cases
randomized controlled trials, the method in which
confounding factors are handled (either through stratification
or appropriate statistical modeling) are of particular
concern. For example, in order to interpret and generalize
conclusions to our population of Medicare patients, it may be
necessary for studies to match or stratify their intervention
and control groups by patient age or co-morbidities.
Methodological strength is, therefore, a multidimensional
concept that relates to the design, implementation and
analysis of a clinical study. In addition, thorough
documentation of the conduct of the research, particularly study
selection criteria, rate of attrition and process for data
collection, is essential for CMS to adequately assess and
consider
the evidence.
Generalizability of Clinical Evidence to the Medicare Population
The applicability of the results of a study to other
populations, settings, treatment regimens and outcomes assessed
is
known as external validity. Even well-designed and
well-conducted trials may not supply the evidence needed if the
results of a study are not applicable to the Medicare
population. Evidence that provides accurate information about a
population or setting not well represented in the Medicare
program would be considered but would suffer from limited
generalizability.
The extent to which the results of a trial are applicable to
other circumstances is often a matter of judgment that
depends on specific study characteristics, primarily the patient
population studied (age, sex, severity of disease and
presence of co-morbidities) and the care setting (primary to
tertiary level of care, as well as the experience and
specialization of the care provider). Additional relevant
variables are treatment regimens (dosage, timing and route of
administration), co-interventions or concomitant therapies, and
type of outcome and length of follow-up.
The level of care and the experience of the providers in the
study are other crucial elements in assessing a study’s
external validity. Trial participants in an academic medical
center may receive more or different attention than is
typically available in non-tertiary settings. For example, an
investigator’s lengthy and detailed explanations of the
potential benefits of the intervention and/or the use of new
equipment provided to the academic center by the study
sponsor may raise doubts about the applicability of study
findings to community practice.
Given the evidence available in the research literature, some
degree of generalization about an intervention’s potential
benefits and harms is invariably required in making coverage
determinations for the Medicare population. Conditions
that assist us in making reasonable generalizations are biologic
plausibility, similarities between the populations studied
and Medicare patients (age, sex, ethnicity and clinical
presentation) and similarities of the intervention studied to
those
that would be routinely available in community practice.
A study’s selected outcomes are an important consideration in
generalizing available clinical evidence to Medicare
coverage determinations. One of the goals of our determination
process is to assess health outcomes. These outcomes
include resultant risks and benefits such as increased or
decreased morbidity and mortality. In order to make this
determination, it is often necessary to evaluate whether the
strength of the evidence is adequate to draw conclusions
about the direction and magnitude of each individual outcome
relevant to the intervention under study. In addition, it is
important that an intervention’s benefits are clinically
significant and durable, rather than marginal or short-lived.
Generally, an intervention is not reasonable and necessary if
its risks outweigh its benefits.
If key health outcomes have not been studied or the direction of
clinical effect is inconclusive, we may also evaluate
the strength and adequacy of indirect evidence linking
intermediate or surrogate outcomes to our outcomes of interest.
Assessing the Relative Magnitude of Risks and Benefits
Generally, an intervention is not reasonable and necessary if
its risks outweigh its benefits. Health outcomes are one of
several considerations in determining whether an item or service
is reasonable and necessary. CMS places greater
emphasis on health outcomes actually experienced by patients,
such as quality of life, functional status, duration of
disability, morbidity and mortality, and less emphasis on
outcomes that patients do not directly experience, such as
intermediate outcomes, surrogate outcomes, and laboratory or
radiographic responses. The direction, magnitude, and
consistency of the risks and benefits across studies are also
important considerations. Based on the analysis of the
strength of the evidence, CMS assesses the relative magnitude of
an intervention or technology’s benefits and risk of
harm to Medicare beneficiaries.
APPENDIX B
Indications and Limitations of Coverage
B. Nationally Covered Indications
1.
The use of CPAP is covered under Medicare when used in adult
patients with Obstructive Sleep Apnea (OSA).
Coverage of CPAP is initially limited to a twelve week period to
identify beneficiaries diagnosed with OSA as
subsequently described who benefit from CPAP. CPAP is
subsequently covered only for those beneficiaries
diagnosed with OSA who benefit from CPAP during this twelve week
period.
35
Date: 6/4/2008, Page 30 of
2.
The provider of CPAP must conduct education of the beneficiary
prior to the use of the CPAP device to ensure
that the beneficiary has been educated in the proper use of the
device. A caregiver, for example a family
member, may be compensatory, if consistently available in the
beneficiary's home and willing and able to safely
operate the CPAP device.
3.
A positive diagnosis of OSA for the coverage of CPAP must
include a clinical evaluation and a positive:
a.
Attended polysomnography (PSG) performed in a sleep laboratory;
or
b.
unattended home sleep test (HST) with a Type II home sleep
monitoring device; or
c.
unattended HST with a Type III home sleep monitoring device; or
d.
unattended HST with () Type IV home sleep monitoring device that
measures at least three channels.
4.
The sleep test must have been previously ordered by the
beneficiary’s treating physician and furnished under
appropriate physician supervision.
5.
An initial twelve week period of CPAP is covered in adult
patients with if either of the following criterion using
the Apnea-Hypopnea Index (AHI) or Respiratory Disturbance Index
(RDI) are met:
a.
AHI or RDI greater than or equal to 15 events per hour, or
b.
AHI or RDI greater than or equal to 5 and less than or equal to
14 events per hour with documented
symptoms of excessive daytime sleepiness, impaired cognition,
mood disorders or insomnia, or
documented hypertension, ischemic heart disease, or history of
stroke.
6.
The AHI or RDI is calculated on the average number of events of
per hour. If the AHI or RDI is calculated
based on less than two hours of continuous recorded sleep, the
total number of recorded events to calculate the
AHI or RDI during sleep testing must be at a minimum the number
of events that would have been required in a
2 hour period.
7.
Apnea is defined as a cessation of airflow for at least 10
seconds. Hypopnea is defined as an abnormal
respiratory event lasting at least 10 seconds with at least a 30
percent reduction in thoracoabdominal movement
or airflow as compared to baseline, and with at least a 4
percent oxygen desaturation.
8.
Coverage with Evidence Development (CED): Medicare provides the
following limited coverage for CPAP in
adult beneficiaries who do not qualify for CPAP coverage based
on criteria 1-7 above. A clinical study seeking
Medicare payment for CPAP provided to a beneficiary who is an
enrolled subject in that study must address one
or more of the following questions
Date: 6/4/2008, Page 31 of
35
a. In Medicare aged subjects with clinically identified risk
factors for OSA, how does the diagnostic
accuracy of a clinical trial of CPAP compare with PSG and Type
II, III & IV HST in identifying
subjects with OSA who will respond to CPAP?
b. In Medicare aged subjects with clinically identified risk
factors for OSA who have not undergone
confirmatory testing with PSG or Type II, III & IV HST, does
CPAP cause clinically meaningful harm?
The study must meet the following additional standards:
c. The principal purpose of the research study is to test
whether a particular intervention potentially
improves the participants’ health outcomes.
d. The research study is well-supported by available scientific
and medical information or it is intended to
clarify or establish the health outcomes of interventions
already in common clinical use.
e. The research study does not unjustifiably duplicate existing
studies.
f. The research study design is appropriate to answer the
research question being asked in the study.
g. The research study is sponsored by an organization or
individual capable of executing the proposed
study successfully.
h. The research study is in compliance with all applicable
Federal regulations concerning the protection of
human subjects found at 45 CFR Part 46. If a study is
FDA-regulated, it also must be in compliance with
21 CFR Parts 50 and 56.
i. All aspects of the research study are conducted according to
the appropriate standards of scientific
integrity.
j. The research study has a written protocol that clearly
addresses, or incorporates by reference, the
Medicare standards.
k. The clinical research study is not designed to exclusively
test toxicity or disease pathophysiology in
healthy individuals. Trials of all medical technologies
measuring therapeutic outcomes as one of the
objectives meet this standard only if the disease or condition
being studied is life-threatening as defined
in 21 CFR § 312.81(a) and the patient has no other viable
treatment options.
l. The clinical research study is registered on the
ClinicalTrials.gov website by the principal
sponsor/investigator prior to the enrollment of the first study
subject.
m. The research study protocol specifies the method and timing
of public release of all pre-specified
outcomes to be measured including release of outcomes if
outcomes are negative or study is terminated
early. The results must be made public within 24 months of the
end of data collection. If a report is
planned to be published in a peer-reviewed journal, then that
initial release may be an abstract that meets
the requirements of the International Committee of Medical
Journal Editors. However, a full report of
the outcomes must be made public no later than three (3) years
after the end of data collection.
n. The research study protocol must explicitly discuss
subpopulations affected by the treatment under
investigation, particularly traditionally underrepresented
groups in clinical studies, how the inclusion
and exclusion criteria affect enrollment of these populations,
and a plan for the retention and reporting
of said populations on the trial. If the inclusion and exclusion
criteria are expected to have a negative
effect on the recruitment or retention of underrepresented
populations, the protocol must discuss why
these criteria are necessary.
o. The research study protocol explicitly discusses how the
results are or are not expected to be
generalizable to the Medicare population to infer whether
Medicare patients may benefit from the
intervention. Separate discussions in the protocol may be
necessary for populations eligible for Medicare
due to age, disability or Medicaid eligibility.
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