Entering the age of portable monitoring.

Two papers have been published recently that propose to change the way portable monitors (PM) are utilized in the diagnosis of obstructive sleep apnea (OSA). In December 2007, an American Academy of Sleep Medicine (AASM) task force published guidelines on the use of PM for the diagnosis of OSA in adults. They recommended that PMs can be used in the context of a comprehensive sleep evaluation when supervised by an appropriately trained sleep specialist in an accredited sleep center utilizing appropriate sensors and quality control.1 The Center for Medicare and Medicaid Services (CMS) issued its national coverage determination policy (NCD) on CPAP coverage in March 2008. This policy states that CMS will pay for CPAP if the diagnosis of OSA in Medicare patients is made using comprehensive in-laboratory polysomnography (type I), unattended comprehensive polysomnography (type II), limited channel PMs (type III), or type IV monitors, which use at least 3 channels. “Improvement in OSA” must be demonstrated at 12 weeks, or CPAP will no longer be covered.2 Given the differences in the two papers, questions have been raised about the compatibility of these two guidelines. Are the AASM recommendations still relevant given the CMS decision? We feel the answer is decidedly yes. The two papers are quite compatible and share more in common than might be thought from first look. Both utilized evidence-based analysis of existing literature to assess the accuracy and validity of PMs in comparison to standard polysomnography. Moreover, both the AASM and CMS reports used expert consensus to recommend how the PMs should be used in the diagnosis of OSA. Nothing in either set of recommendations conflicts with the other. The AASM task force conducted an evidence-based review focusing on type III monitors, since they felt there had not been sufficient new evidence since the last AASM evidence-based review in 20033 to warrant reevaluating type II and IV PMs. They concluded the evidence concerning type III monitors supported their use in the diagnosis of OSA under certain circumstances. CMS relied on a separate evidence analysis conducted by the Agency for Healthcare Research and Quality (AHRQ).4 This report also concluded there was evidence to show that type II and III monitors may have the ability to detect an apnea-hypopnea index (AHI) predictive of OSA, and that patients diagnosed with OSA by these types of portable monitors would have outcomes similar to those diagnosed with polysomnography. The evidence regarding type IV monitors was weaker, which led CMS to only approve type IV monitors if they utilize 3 channels (though there is no data provided on which monitors met this criteria). Overall, both papers concluded the time had come to figure out how to incorporate PMs into the clinical management of OSA. The recommendations of the AASM task force on how to use PMs were constructed taking into account several potential problems. The studies on PMs had, by and large, been performed in populations at high risk for OSA, excluded patients with comorbid medical conditions and other sleep disorders, used predominantly younger and male patients, utilized a screening evaluation prior to testing, and showed higher failure rates for PMs than polysomnography. These inadequacies in the studies have the potential to lead to false positive and negative diagnoses. The AHRQ report noted the same limitations. The AASM task force accounted for these limitations in their Clinical Guideline. They felt the best way to maintain high quality care and limit error and false diagnosis was to use PMs in clinical conditions similar to those used in the research trials until more information is available on the accuracy of their use in more diverse populations. Therefore, they recommended limiting use of PMs to those patients with a high pretest probability of moderate to severe OSA and no other potentially confounding medical conditions or sleep disorders. In addition, they recommended technical standards for conducting home testing that would maintain the same high standards and clinical efficacy as found in an accredited sleep center. The best way to insure the PMs are used correctly is to have them performed by clinicians trained in their use, who already employ quality assurance testing, and who are familiar with the appearance and causes of artifact and spurious signals. As of now, the best marker of training in the use of these devices is board certification in sleep medicine, either from the American Board of Medical Specialties or American Board of Sleep Medicine. The best marker of high-quality test performance and ongoing quality monitoring is accreditation of sleep centers by the AASM. Thus, the recommendation of the AASM task force included these qualifiers. CMS evaluated the evidence-based technology assessment of the AHRQ and made their own clinical recommendations. Their recent NCD on CPAP coverage was a statement on how to qualify for reimbursement for CPAP therapy. In this NCD they viewed testing as a way to identify patients who will respond clinically to CPAP therapy. Though no test was predictive of response to therapy, they concluded that multiple types of devices could determine an AHI/RDI suggestive of the clinical syndrome of OSA with sufficient accuracy. Therefore they changed their policy to reimburse CPAP when therapy is predicated on a diagnosis made using type I, II, and III devices, and type IV devices (with 3 channels). Most importantly, they included a requirement that patients be monitored for response to therapy. They will not reimburse for CPAP therapy after 12 weeks unless benefit is demonstrated. This last requirement is probably the most important. They recognize that OSA is a chronic disease requiring long-term management. Care strategies should include longitudinal disease management and focus on outcomes. The focus on chronic disease management and outcome measures is wholly consistent with the AASM task force recommendations and other AASM policies. The AASM Clinical Guideline states that a follow-up visit should be performed on all patients undergoing PM and PM should only be performed in conjunction with a comprehensive sleep evaluation. In the absence of a comprehensive sleep evaluation, the Guideline states, there is no indication for the use of PMs. Similarly, the Practice Parameters concerning the use of PAP therapy state that patients treated with PAP should have close follow-up by appropriately trained health care providers, especially in the first few weeks, and usage should be monitored objectively to assure adherence.5 Of note, the CMS NCD did not comment on: (1) how to perform PM, (2) how to measure benefit from CPAP therapy, or (3) the qualifications of, or the restrictions on, those performing these tests. They specifically referred those questions to others to determine, stating: “Medicare contractors may develop local strategies to ensure that these services are only provided in a manner consistent with the NCD…” and “Medicare contractors may determine what documentation may be required…” This leaves the specifications on how to perform PM for Medicare patients to the regional Medicare carriers. It is this lack of detail on performing PM that is the cause of the differences between the AASM Clinical Guideline and the CMS NCD. The AASM task force went further in trying to describe ideal clinical practices that will ensure diagnostic accuracy and provision of high quality care. These two guidelines represent a shift in clinical practice with regard to the diagnosis and management of patients with OSA. New technology is being incorporated into diagnostic strategies. The AASM Clinical Guideline provides a path to accomplish this while assuring high quality, cost effective care. In addition, the guidelines highlight the need to focus on chronic disease management and outcomes-based strategies while taking care of patients with OSA. These aims are highly consistent and very relevant to the CMS NCD for CPAP therapy.