A sleep physician addresses some of the issues, including benefits, limitations, and reimbursement.

In the January 2015 issue of Sleep Review (SR) I addressed many aspects of home sleep testing (HST), also known as unattended limited channel polysomnography, including indications and exclusion criteria, advantages and limitations, analysis of results, situations that may require attended PSG or PAP titration based on the HST results and/or treatment outcomes, terminology, payor and regulatory issues, technical aspects, business models, cost considerations, the role of HST in dentistry, and some of the challenges still facing the many stakeholders in the sleep medicine community.

In the Nov 14 and Jan 15 issues of SR I reviewed various aspects of the HST direct to auto-adjusting CPAP (APAP) model and suggested a decision tree for screening, analyzing, and acting on the results of the HST and criteria for when APAP is (or not) appropriate and a protocol for follow up if APAP therapy is started based on the HST.

The intent of this article is to address several questions that arose during a recent webinar on HST presented by SR (“Cashing in on Home Sleep Testing”). The questions concern issues related to multiple night HST (MN-HST) and which I have restated here for purposes of structure and clarity—namely benefits, limitations, and billing/reimbursement issues. My comments are based on the assumption that HST is used for its intended purpose, ie, testing patients at risk for obstructive sleep apnea (OSA), and while I have tried to provide a balanced view some of the commentary reflects my own view of the issues.

First let’s differentiate the MN-HST that is typically a 2- or 3-night study performed on consecutive nights from a repeat or follow-up HST performed on different nights.

The latter, from a medical viewpoint, is more clear-cut. Some of the indications for repeat HST include “significant” weight loss, change in symptoms, and evaluation of the effectiveness of oral appliances or surgical procedures. In these situations reimbursement policies vary among payors based on indications, number of studies permitted (if any), and time periods between studies. The problem is further compounded for patients when changing their health insurance plans. Redoes for failed studies or technical problems are typically absorbed by providers as a cost of doing business.

For MN-HST there are additional issues. Some but not all HST devices have the built-in capability to record consecutive multi night studies, and although some but not all payors reimburse more for the technical component of MN-HST most do not pay a higher interpretation fee. In our experience MN-HST usually does not provide sufficient additional information compared to the single-night study to justify the additional cost. Also, most providers are not inclined to tie up their equipment longer for a MN-HST. After all, even attended polysomnography (PSG) is only a single-night study with limited sensitivity and specificity (as is HST) based on definitions of respiratory events, severity of OSA, night-to-night variability, and other issues. And, if there are questions about the results of a single-night HST performed on a patient at high risk for OSA, attended PSG should be recommended.

A 2013 review article on HST for OSA addressed the question of MN-HST compared to single-night HST and suggested that night-to-night variability due to multiple possible causes may result in misclassification of OSA severity when determined by a single-night study and that an aggregate value based on the range of AHI values determined during a MN-HST might have some benefit for more accurately determining the severity of OSA. However the authors indicated that available studies of the issue have been inconsistent due to the limited number of patients studied and the use of different testing devices. They also concluded that there is a need for additional research to clarify the role of multi night testing and, with the absence of strong evidence to the contrary as well as cost containment issues, major challenges justifying MN-HST remain (Chest. 2013 Feb; 143(2): 291–94). In light of these limitations, it appears that at least for the present time, single-night HST is more practical in most situations. Furthermore it is more difficult to compare AHI results across a MN-HST as most devices do not measure, or only indirectly estimate, sleep time. It has been suggested that MN-HST may be more useful in populations such as pediatric, elderly, or other immobile populations. An older study of night-to-night variability of disturbed breathing during sleep in elderly residents of a retirement village who had no clinical features to suggest OSA showed that there was little effect on classification of groups with RDI ? 25 vs > 15 (Sleep. 1991 Jun; 14(3):252-8).



In my view much of this is academic as practically speaking even 2- to 3-night MN-HST may not over the long term be sufficient to account for the many factors affecting night-to-night variability. So regardless of the type of study (whether single-night HST, MN-HST, or PSG) all patients started on CPAP, BiLevel PAP, or APAP should have periodic PAP data downloads as long as they are on therapy (more frequently at first) reviewed by the physician and equipment supplier to monitor usage, leak, and respiratory events and adjust the PAP setting appropriately. Also, where indicated, periodic overnight oximetry should be recorded during treatment to assure correction of O2 desaturations (eg, oral appliances, high PAP requirements, low SpO2 during titrations, patients started on APAP based on HST results, and patients with underlying lung or cardiac disease).

Improved quality of life and both subjective and objective clinical improvement are the ultimate goals. We must remember that any sleep test is but one aspect of the larger picture that includes education, screening, testing, treatment, monitoring, outcome evaluation, and follow up. Regardless of the particular type of sleep test employed, it is important to have a formal protocol in place and a network of healthcare professionals capable of providing all aspects of care for patients with OSA.

Edward D. Michaelson, MD FACP FCCP FAASM, is based in Ft Lauderdale, Fla, and a member of Sleep Review’s Editorial Advisory Board.