Home Sleep Testing: A Five Minute Primer On What Everyone's Arguing About
Even though CMS is expected to publish a new decision memorandum in December about Medicare coverage for home sleep testing to diagnose obstructive sleep apnea (OSA), the heated debate continues among physicians, researchers, statisticians, DME providers and CMS. The controversy has maintained a high profile in the respiratory-care sector of the DME industry since 2004 when a physician at the University of California San Diego School of Medicine formally asked CMS to permit Medicare coverage of portable, multi-channel home sleep testing devices as an alternative to sleep-lab tests (polysomnography).
If you haven't had time to follow the issue closely, here's a five-minute primer that will catch you up on the scuffle over in-home sleep testing.
The essential question that everyone is arguing about is whether unattended tests designed to detect OSA that patients take at home are as reliable a basis for diagnosis as sleep-lab polysomnography. The sides generally line up like this: the DME industry favors the at-home tests, as do many physicians and some medical associations, such as the American Academy of Otolaryngology-Head and Neck Surgery. Other medical organizations remain opposed; they include the Sleep Research Society and the New England Polysomnographic Society.
Since both sides cite published research studies that support their positions, the evidence obviously is not definitive. While the recent literature does show a generally high correlation of results from sleep-lab and at-home studies, the at-home studies have not actually been done unattended in patients' actual homes. Polysomnography advocates worry that at-home studies use too few of what sleep specialists call channels -- data inputs from sensors, such as airflow, heart rate, ventilation, ECG, and oxygen saturation -- to positively diagnose OSA. Sleep labs use more than 10 channels, at-home tests only four. Proponents say four is enough.
So far, CMS has sided with at-home testing skeptics. Here's how the agency put it in the decision that has, until now, been the basis for Medicare policy: "The evidence is not adequate to conclude that the use of unattended portable multi-channel sleep testing with a minimum of four monitored channels including ventilation or airflow, heart rate or ECG, and oxygen saturation (Type III Devices based on the 1994 ASDA classification system) is reasonable and necessary in the diagnosis of OSA and these tests will remain noncovered for this purpose."
It's this position that at-home-testing enthusiasts hope will change in March.
One of the main arguments that proponents advance is that the American OSA population is enormous and largely undiagnosed. Testing the potentially thousands of people who could benefit from CPAP therapy could overwhelm sleep labs. They also contend that many patients suspected of suffering from OSA aren't enthusiastic about snoozing for an audience away from home.
"Polysomnography . . . is an expensive test that can only be done in a sleep center that accommodates overnight testing," argues the American Academy of Otolaryngology Head and Neck Surgery. "In addition to requiring an overnight stay, some patients may be limited by geographic accessibility to an appropriate sleep lab."
Specialists continue arguing about sleep testing because, as CMS noted in its 2005 Decision Memorandum, "There is no anatomic or physiologic 'gold standard' for the diagnosis of obstructive sleep apnea, in contrast to conditions such as cancer where a tissue biopsy result is the definitive standard reference."
An independent committee commissioned by CMS to assess the relevant medical literature on the relative merits of lab and at-home testing ran into problems. ". . . Most articles only provided information on the use of portable monitoring devices in the laboratory setting when performed simultaneously with polysomnography. These studies do not provide information on the use and performance of portable monitoring devices unattended in the patients' home," CMS reported. "The studies evaluated reported a wide range of data loss results for in-home studies. The literature reviewed suggests that data loss appears to be greater when the patient performs set-up of the equipment. Results obtained from automated portable device scoring appear to provide less agreement with polysomnography than does manual scoring. More evidence is needed to reach conclusions about the effect of co-morbidities, age, patient versus technician performed hookup on the overall effectiveness of home studies in diagnosing OSA compared to in-laboratory PSG."
In other words, the jury's still out.
This article originally appeared in the September 2007 issue of HME Business.