Effects of Suboptimal Adherence of CPAP-Therapy on Symptoms of Obstructive Sleep Apnea: A Randomized, Double-Blind, Controlled Trial

Abstract

Background: Continuous positive airway pressure (CPAP) is currently the treatment of choice for sleepiness in patients with obstructive sleep apnea (OSA), however, adherence is often thought to be suboptimal. We investigated the effects of suboptimal CPAP-usage on sleepiness parameters in patients with OSA. Methods: In this 2-week, parallel, double-blind, randomized controlled trial we enrolled moderate-to-severe OSA patients with excessive pre-treatment daytime sleepiness (ESS score >10) who had suboptimal CPAP adherence over at least 12 months (mean nightly usage time 3-4 hours). Patients were allocated through minimization to either CPAP-withdrawal (sham-CPAP) or continuation of CPAP (therapeutic-CPAP). A Bayesian analysis with historical priors calculated the posterior probability of superiority. Findings: Between May 27, 2016 and November 10, 2018, 57 patients (60±8 years, 79% men, 93% Caucasian) were allocated in total, and 52 who completed the study (50% in each arm) were included in the final analysis. The unadjusted ESS-score increase was +2.9 points (95% CI +1.3 to +4.7; p=0.001) in the sham-CPAP-group when compared to continuing therapeutic CPAP. The probability of superiority of therapeutic CPAP over sham CPAP was 97.6% for ESS, 90.1% for systolic, and 80.3% for diastolic blood pressure. Conclusion: Patients with moderate-to-severe OSA and daytime sleepiness are still getting a substantial benefit from suboptimal CPAP adherence, albeit not as much as they might get if they adhered more. Whether a similar statement can be made for even lower adherence levels remains to be established in future trials. Trial Registration Number: The trial was pre-registered at ClinicalTrials.gov (NCT02781740) Funding Statement: Swiss National Science Foundation (grant no. 32003B_162534). Declaration of Interests: JRS reports personal fees from Resmed UK, personal fees from Bayer Germany, outside the submitted work. MK reports grants from University of Zurich, grants from Lunge Zurich, during the conduct of the study; grants from Bayer AG, outside the submitted work. TG reports personal fees from Bayer AG, outside the submitted work. All other authors report no conflict of interest. Ethics Approval Statement: All tests were conducted by the University Hospital Zurich and approved by the cantonal ethics committee of Zurich (KEK-ZH-Nr. 2016-00332). All patients provided written informed consent according to the Declaration of Helsinki. Data were obtained according to Good Clinical Practice (GCP) guidelines.