Effect of liraglutide 3.0 mg in individuals with obesity and moderate or severe obstructive sleep apnea: the SCALE Sleep Apnea randomized clinical trial

BACKGROUND: Obesity is strongly associated with prevalence of obstructive sleep apnea (OSA), and weight loss has been shown to reduce disease severity. OBJECTIVE: To investigate whether liraglutide 3.0 mg reduces OSA severity compared with placebo using the primary end point of change in apnea–hypopnea index (AHI) after 32 weeks. Liraglutide's weight loss efficacy was also examined. SUBJECTS/METHODS: In this randomized, double-blind trial, non-diabetic participants with obesity who had moderate (AHI 15–29.9 events h(−1)) or severe (AHI ⩾30 events h(−1)) OSA and were unwilling/unable to use continuous positive airway pressure therapy were randomized for 32 weeks to liraglutide 3.0 mg (n=180) or placebo (n=179), both as adjunct to diet (500 kcal day(−1) deficit) and exercise. Baseline characteristics were similar between groups (mean age 48.5 years, males 71.9%, AHI 49.2 events h(−1), severe OSA 67.1%, body weight 117.6 kg, body mass index 39.1 kg m(−2), prediabetes 63.2%, HbA(1c) 5.7%). RESULTS: After 32 weeks, the mean reduction in AHI was greater with liraglutide than with placebo (−12.2 vs −6.1 events h(−1), estimated treatment difference: −6.1 events h(−1) (95% confidence interval (CI), −11.0 to −1.2), P=0.0150). Liraglutide produced greater mean percentage weight loss compared with placebo (−5.7% vs −1.6%, estimated treatment difference: −4.2% (95% CI, −5.2 to −3.1%), P<0.0001). A statistically significant association between the degree of weight loss and improvement in OSA end points (P<0.01, all) was demonstrated post hoc. Greater reductions in glycated hemoglobin (HbA(1c)) and systolic blood pressure (SBP) were seen with liraglutide versus placebo (both P<0.001). The safety profile of liraglutide 3.0 mg was similar to that seen with doses ⩽1.8 mg. CONCLUSIONS: As an adjunct to diet and exercise, liraglutide 3.0 mg was generally well tolerated and produced significantly greater reductions than placebo in AHI, body weight, SBP and HbA(1c) in participants with obesity and moderate/severe OSA. The results confirm that weight loss improves OSA-related parameters.