Mandibular advancement device versus CPAP in lowering 24-hour blood pressure in patients with obstructive sleep...

Although treatment of obstructive sleep apnoea (OSA) using continuous positive airway pressure (CPAP) reduces blood pressure (BP), adherence to CPAP is often suboptimal. A mandibular advancement device (MAD) is a guideline-endorsed alternative therapy for OSA. Still, there is limited evidence on the relative efficacy between MAD and CPAP on BP reduction. We evaluate whether treatment of moderate-to-severe OSA using MAD can improve BP and other health-related outcomes compared with CPAP.

This is a randomised, controlled, non-inferiority trial conducted. We will recruit 220 Asians with a history of hypertension and high cardiovascular risk for an overnight polysomnography screening. Those with moderate-to-severe OSA (apnoea-hypopnoea index ≥15 events/hour) will be randomised to treatment with either MAD or CPAP in a 1:1 ratio. Stratified by age (60 vs <60 years old), body mass index (25 vs <25 kg/m²) and apnoea-hypopnoea index (30 vs <30 events/hour), an adaptive randomisation scheme with permuted blocks constructed in real-time is implemented to restrict imbalance. The overall study duration is 12 months. The primary endpoint is the 24-hour mean arterial BP difference between baseline and 6-month follow-up. The secondary endpoints include other measures of ambulatory BP monitoring, arrhythmia based on a 4-day electrocardiographic monitoring, biomarker and proteomic analysis, cardiovascular magnetic resonance-derived myocardial fibrosis and remodelling and quality-of-life questionnaires. Recruitment began in October 2019 and ended in December 2022. Comparison between MAD and CPAP will be performed using covariance (ANCOVA) analysis of the changes in 24-hour mean arterial BP while adjusting for the baseline 24-hour mean arterial BP. We will compare the 95% CIs around the treatment difference point estimate with the prespecified non-inferiority margin (1.5 mm Hg). If the upper limit of the 95% CI is <1.5 mm Hg and crosses 0, non-inferiority of the MAD relative to CPAP will be established.

The Domain Specific Review Board-C, National Healthcare Group under approved the study protocol (NHG DSRB Ref: 2019/00359, approved on 28 August 2019). Study findings will be disseminated to various local, national, and international audiences through abstract presentations and publication in peer-reviewed journals.

NCT04119999.