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Blue Light Special on CPAP, Aisle 11 FREE TO VIEW

Nancy A. Collop, MD, FCCP
Author and Funding Information

Affiliations: Baltimore, MD
 ,  Dr. Collop is Associate Professor of Medicine, Division of Pulmonary/Critical Care Medicine, Johns Hopkins University.

Correspondence to: Nancy Collop, MD, FCCP, Associate Professor of Medicine, Division of Pulmonary/Critical Care Medicine, Johns Hopkins University DOM, 1830 E Monument St, Room 555, Baltimore, MD 21205; e-mail: ncollop@jhmi.edu

Chest. 2006;129(1):6-7. doi:10.1378/chest.129.1.6
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Published in this issue of CHEST (see page 67) is a provocative study by Senn et al1 in which the authors initiated a trial with an autotitrating continuous positive airway pressure (CPAP) device prior to a diagnostic study for sleep-disordered breathing, testing the hypothesis that those with “significant” obstructive sleep apnea (OSA) would have a positive response to CPAP therapy, thereby potentially obviating the need for polysomnography or definitive diagnostic testing. Senn et al found that 46% of their study population had both OSA, ultimately documented by polysomnography, and a “positive CPAP trial.”

The authors make a number of arguable assumptions in this article. First, they state that polysomnography is “not readily available.” This article is from Europe (Switzerland), where the availability may be different; but in the United States, I would argue, polysomnography is not that difficult to access. In an unpublished survey from the American Academy of Sleep Medicine including > 1,000 sleep centers in the United States, the average wait time for a polysomnography was approximately 22 days. This is certainly no longer than the wait for an elective cardiac catheterization or similar elective procedure. Second, another assumption is that the only important information gleaned from polysomnography is the diagnosis of OSA. I have personally discovered many things on polysomnography beyond the formulation of an apnea-hypopnea index, such as arrhythmias, including atrial fibrillation and prolonged (ie, > 5 s) sinus pauses; arousing periodic limb or body movements; profound oxygen desaturation; and a Cheyne-Stokes breathing pattern, to name a few. Of course, one must actually look at the polysomnography to find these things, but, alas, that is for a different editorial.

There are also a number of problems with the study design that weaken its import. There is no control arm, so we do not know whether patients who underwent a sleep study first would be more or less likely to initially use CPAP. The informed consent procedure was not discussed; did the patients know that they would eventually be undergoing the diagnostic study anyway? If so, that would eliminate the uncertainty associated with wearing a machine for a disorder that you may or may not have. In this study population, there was only one “false-positive” result, but a larger and less selected population may have had significantly more false-positive results, thereby unnecessarily labeling and treating patients for a disease they do not have.

The exclusion criteria were also quite broad; in fact, in this group of patients who had been referred for a sleep apnea evaluation, only 39% of the population was included, suggesting a quite select group. In fact, of the patients referred, < 18% were positive CPAP responders (35 of 195 successive patients). And, finally, in the group of patients who responded positively to CPAP therapy, the authors note that those patients were extremely likely to continue to use CPAP after 4 months of follow-up (33 of 35 patients continued CPAP use). It is important to note, however, that all of these patients knew during those 4 months that they indeed had OSA (they were unblinded), so they were not really much different than any group of CPAP users at that point. How would they have responded to therapy if they had not known their diagnosis? This is an important unanswered question.

Despite these issues, I applaud the authors on this innovative approach to the management of OSA. There are undoubtedly situations in which this approach is warranted, particularly in countries or even in parts of the United States where access to sleep laboratories may be limited. However, the notion of treating a disease like OSA without documenting its existence is a bit unnerving to me. The authors use the examples of the empiric treatment of patients with gastroesophageal reflux disease and infectious diseases as similar “prevalent and treatable conditions” in which successful treatment also serves as a diagnosis. The difference is that infectious diseases are clearly of an intermittent nature, not a lifelong condition like OSA. And although gastroesophageal reflux disease is often a chronic condition, its association with significant long-term adverse consequences such as those from Barrett’s metaplasia and esophageal cancer is relatively uncommon. In contrast, OSA is typically a lifelong condition for most patients, and is associated with several cardiovascular diseases and increased mortality. It is hard to imagine treating patients with CPAP for prolonged periods of time without a definitive diagnosis. In the United States, one can only imagine what might come next. Since CPAP “has no serious side effects,” why not just let durable medical equipment companies offer “CPAP service trials?” Or perhaps, deregulate the device and allow drug stores or large retail stores like Kmart and Wal-Mart to sell CPAP as a “sleep aid.” Imagine hearing: “Attention shoppers: blue light special on CPAPs, aisle 11!”

In conclusion, a serious and highly morbid disease like OSA should not go undiagnosed simply because the therapy is relatively benign. Patients deserve to know the severity and potential impact of their disease. This is the usual approach that modern medicine takes for the vast majority of lifelong medical disorders. Empiric treatment of OSA with CPAP minimizes the importance of the diagnosis and would create more confusion for patients in the long run. Although empiric CPAP therapy such as that used in the current study by Senn et al likely has a role in special circumstances, I believe it should not be used in the long term without establishing a diagnosis.


Senn, O, Brach, T, Russi, EW, et al (2006) A continuous positive airway pressure trial as a novel approach to the diagnosis of obstructive sleep apnea syndrome.Chest129,67-75. [CrossRef] [PubMed]




Senn, O, Brach, T, Russi, EW, et al (2006) A continuous positive airway pressure trial as a novel approach to the diagnosis of obstructive sleep apnea syndrome.Chest129,67-75. [CrossRef] [PubMed]
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