Dixon Yang, MD
Obstructive sleep apnea (OSA) is common in stroke/transient ischemic attack (TIA) survivors. Untreated OSA can increase risk of cardiovascular disease, including recurrent stroke, and lead to worse functional outcomes. Yet, OSA remains underdiagnosed after stroke. Barriers to diagnosis may include patient inconvenience and cost of an in-laboratory polysomnography (iPSG); therefore, Boulos et al. sought to compare the diagnostic performance of a home sleep apnea test (HSAT) in SLEAP SMART.
The primary objective of SLEAP SMART was to determine the proportion of OSA diagnosed at 6 months after stroke/TIA using HSAT as compared to iPSG. Secondarily, the trial sought to evaluate if screening for OSA with HSAT when compared to iPSG led to increased CPAP prescription, reduced daytime sleepiness, improved sleep-related quality of life, improved functional outcomes, improved patient experience with the sleep test, and cost-effectiveness for the diagnosis of OSA. Participants were recruited from 2015-2017 at a single Canadian center who had imaging-confirmed stroke or stroke-physician diagnosed TIA within the last 6 months. Exclusion criteria were a prior diagnosis of OSA, current CPAP use, comorbidities or use of medical devices that could compromise HSAT accuracy, barriers to complying with CPAP therapy, and significant physical or cognitive impairment. Eligible patients were randomized 1:1 to iPSG or HSAT. OSA was defined as apnea-hyponea index ≥15 or apnea-hyponea index ≥5 with a lowest oxygen desaturation ≤88%. Primary outcomes were compared using intention-to-treat analysis.
A total of 125 patients were randomized to each study arm. At 6 months, 94 patients completed HSAT and 71 patients completed iPSG. More patients using HSAT were diagnosed with OSA (49% vs 35%, p=0.04) and prescribed CPAP (risk difference 0.13 [95% CI 0.004-0.252], p=0.045) when compared to the iPSG arm. Secondarily, patients using HSAT had lower daytime sleepiness at 6 months measured by Epworth Sleepiness Scale (beta -1.13 [95% CI -2.17 to -0.09], p=0.033]. There were no substantial differences in functional outcomes. More patients reported HSAT as a positive experience than iPSG compared with their usual sleep at home. Importantly, HSAT was more cost-effective for detection of OSA from a net benefit regression framework, with mean HSAT cost at about $200 CAD ($161 USD) and iPSG mean cost about $493 CAD ($398 USD).
SLEAP SMART is currently the first randomized control trial in stroke/TIA patients comparing HSAT to iPSG. The authors concluded that HSAT increased the rate of OSA diagnosis and treatment, reduced daytime sleepiness, and was more cost-effective when compared to iPSG. HSAT also has the potential added advantage of convenience and low wait times. Further, an ambulatory approach may be especially preferred during a pandemic. There may be limitations in generalizability given their selection of patients without physical and cognitive impairments, and cost-effectiveness was analyzed in the context of a Canadian public health care payer; however, the trial provides important results on a potentially more accessible route to OSA diagnosis after stroke.
