COMMENTARY
More Isn’t Always Better: Cost-Effectiveness Analysis and the Case for Using a
Split-Night Protocol
Vishesh K. Kapur, M.D., M.P.H.1; Sean D. Sullivan, Ph.D.2
Department of Medicine; 2Departments of Pharmacy and Health Services, University of Washington, Seattle, WA
1
Commentary on Deutsch PA; Simmons MS; Wallace JM. Cost-effectiveness of split-night polysomnography
and home studies in the evaluation of obstructive sleep apnea syndrome. J Clin Sleep Med 2006;2(2):145153.
A
s sleep physicians, we should be concerned about not only the
improvement of our patients’ health but also whether we are
unnecessarily burdening our patients or society with treatments
that do not provide good value for money. This is particularly important in the case of the diagnosis of and initiation of continuous
positive airway pressure (CPAP) treatment for obstructive sleep
apnea because the high prevalence of undiagnosed disease, as
well as the high costs of the standard approach (2 nights of polysomnography), impose a significant economic burden on society.
A number of alternative strategies for the diagnosis and treatment
initiation are available. The debate about which approach is the
best is a contentious one and may be obscured by issues that include physicians’ familiarity with strategies or personal financial
incentives.
Cost-effectiveness analysis is a technique that provides a
framework for assessing value for money among alternative treatment strategies. It summarizes relevant information to determine
how to best allocate limited healthcare resources. Unfortunately,
this estimation technique is not immune to bias and inaccuracy. Its
trustworthiness depends on the skill of the analysts, the development of a realistic decision tree, and the use of data from valid
studies in the medical literature. Of particular concern is when objective data are insufficient or not available in the medical literature and “reasonable” assumptions based on experience are made.
We need to become familiar with cost-effectiveness analysis as
a tool, given its possible use by those who control and allocate
healthcare resources.
In this issue of the Journal of Clinical Sleep Medicine, Deutsch
et al1 provide a useful cost-effectiveness analysis that compares
the standard approach with 2 alternative methods of diagnosing
and initiating treatment for sleep apnea.1 The analysis presented is
unique in that it includes split-night polysomnography (PSG) as
one of the methods. Split-night PSG is a sleep study during which
the first 2 or more hours of the sleep period are used to assess
obstructive sleep apnea, and, if criteria are met, CPAP titration is
performed during the remainder of the night. Otherwise, a second
standard CPAP-titration study is performed. A second CPAP-titration study can also be performed if the initial titration is incomplete. Evidence-based practice parameters by the American
Academy of Sleep Medicine include the split-night PSG protocol
as an acceptable alternative to the standard approach.2 Nevertheless, surveys suggest that this approach is not routinely used by
many sleep physicians.3
The authors found that the standard and split-night PSG strategies provide additional gains in quality-adjusted life expectancy
(QALY) at an acceptable cost when compared with home-based
study followed by CPAP autotitration. This analysis, as well as
previously published studies in this area, demonstrate that the
diagnosis and treatment of OSA are cost-effective in a clinic
population with a high prevalence of symptomatic patients with
moderate to severe obstructive sleep apnea, when compared with
other accepted medical interventions such as the use of antihypertensive medication.4
Which approach is the most cost-effective? The analysis by
Deutsch et al suggests that the standard approach or split-night
PSG provides similar value and is preferred over home-based
study when willingness to pay for an additional quality-adjusted
year of survival is greater that $6500. Though the standard approach provides additional benefit in terms of QALY over splitnight PSG, the magnitude is very small (0.02 QALY or 7 additional quality-adjusted days of survival). This suggests that, even
if the incremental cost-effectiveness of the standard approach
compared with split-night PSG is acceptable, the additional benefit gain is small and may not be clinically relevant. Also, even
though the additional benefit of using the standard approach over
the home-based sleep study is greater in magnitude (0.10 QALY
or 36 quality-adjusted days of survival), it is still small relative to
the benefit provided by the least-expensive approach (2.23 QALY
or 814 quality-adjusted days of survival).
One can even question the finding of minimal additional ben-
Disclosure Statement
Dr. Kapur has received research support from Pro-Tech Services, Inc.; and
has received free use of equipment from Respironics. Dr. Sullivan has indicated no financial conflict of interest.
Address correspondence to: Vishesh K. Kapur, M.D., M.P.H., UW Sleep Disorder Center, Box 359803, 325 Ninth Avenue, Seattle, WA 98104-2499; Tel:
(206) 731-4999; Fax: (206) 731-5657; E-mail: [email protected]
Journal of Clinical Sleep Medicine, Vol. 2, No. 2, 2006
154
Cost-Effectiveness of Split-Night Protocols
efit of the standard method. The sensitivity analysis from the current study indicates that the relative CPAP acceptance rate of patients who use the standard approach versus a split-night PSG is
an important one in determining which approach is superior. The
authors chose a higher acceptance rate for the standard approach,
even though retrospective controlled studies indicate similar acceptance rates and CPAP compliance.5 There are no randomized
prospective comparisons of these approaches to inform us, with
adequate certainty, whether there are differences in long-term
compliance between the approaches. The split-night approach
may in fact be the superior method (lower cost with equal or
greater benefit).
Cost-effectiveness analysis alone, though informative, can not
adequately resolve the controversy concerning which of the 3
strategies to use because of insufficient experimental data. Wellpowered, randomized, controlled trials of treatment efficacy that
collect data on quality of life, health, and economic outcomes are
needed to provide more-accurate inputs for a cost-effectiveness
analysis. Ideally, these trials would include subjects with the full
spectrum of obstructive sleep apnea severity and, therefore, also
provide data on the cost-effectiveness of the diagnosis and treatment of patients with mild obstructive sleep apnea. The value of a
randomized controlled trial is highlighted by a recent study of alternative CPAP-titration options by Masa et al.6 The results of this
study contradicted the conventional assumption that the standard
(most resource intensive) approach is the best; CPAP compliance,
as well as improvements in subjective sleepiness and apnea-hypopnea index, were similar in groups that had CPAP pressures
chosen by polysomnography, autotitrator, or a prediction formula.
The sleep community needs to vigorously pursue clinical trials to
evaluate split-night and other potentially resource-saving methods such as home-testing options so we that have the information
to appropriately treat our patients.
As sleep physicians, we have a responsibility to our patients
to provide them with optimal care without wasting their money
and time. We also have a responsibility to society to use shared
resources wisely. Previous studies have indicated that a splitnight protocol provides similar summary information with regard
to indexes of sleep-disordered breathing and comparable results
in CPAP acceptance, long-term adherence, and nightly use.5 In
this issue, Deutsch et al present a cost-effectiveness analysis that
shows that split-night-PSG provides benefits similar to those of
the standard approach at a lower cost. We should not wait for outside parties to tell us how to use resources wisely. We need to
ignore personal economic incentives and utilize a strategy that
saves money and reduces patient inconvenience and time to effective treatment by potentially eliminating the need for a second
study night.7
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REFERENCES
1.
2.
3.
Deutsch PA, Simmons MS, Wallace JM. Cost-effectiveness of splitnight polysomnography and home studies in the evaluation of obstructive sleep apnea syndrome. J Clin Sleep Med 2006;2(2):14553.
Kushida CA, Littner MR, Morgenthaler T, et al. Practice parameters
for the indications for polysomnography and related procedures: an
update for 2005. Sleep 2005;28:499-521.
Chervin RD, Moyer CA, Palmisano J, et al. Sleep-disordered breathing in Michigan: a practice pattern survey. Sleep Breath 2003;7:95104.
Journal of Clinical Sleep Medicine, Vol. 2, No. 2, 2006
155
Neumann PJ, Levine BS. Do HEDIS measures reflect cost-effective
practices? Am J Prev Med 2002;23:276-89.
Rodway GW, Sanders MH. The efficacy of split-night sleep studies.
Sleep Med Rev 2003;7:391-401.
Masa JF, Jimenez A, Duran J et al. Alternative methods of titrating
continuous positive airway pressure: a large multicenter study. Am
J Respir Crit Care Med 2004;170:1218-24.
Elshaug AG, Moss JR, Southcott AM. Implementation of a splitnight protocol to improve efficiency in assessment and treatment of
obstructive sleep apnoea. Intern Med J 2005;35:251-4.