Effect of Continuous Positive Airway Pressure on Weight and Local Adiposity in Adults with Obstructive Sleep Apnea: A Meta-Analysis.

Rationale: Evidence suggests that continuous positive airway pressure (CPAP) treatment promotes weight gain in patients with obstructive sleep apnea (OSA). It is unclear whether weight gain is influenced by CPAP adherence or comorbid disorders. Objectives: To examine the CPAP effects on body mass index (BMI) and local adiposity and the potential moderators of CPAP effects on BMI in patients with OSA. Methods: We searched PubMed/Medline, Embase, and Cochrane through December 2019. Randomized controlled trials of CPAP versus control treatment with ⩾4 weeks' treatment were included. Results: A total of 39 randomized controlled trials with 6,954 subjects were included. In intention-to-treat analysis, the BMI increased significantly after CPAP treatment compared with control treatment (weighted mean difference [WMD], 0.148 kg/m2; 95% confidence interval, 0.04-0.26; P = 0.001). In studies demonstrating an increase in the BMI, waist and neck circumferences were also significantly increased. Subgroup analyses revealed that an increased BMI was attributable to CPAP use of ⩽5 h/night (WMD, 0.231) but was not attributable to CPAP use of >5 h/night (WMD, 0.001; between-group P value = 0.049). Furthermore, the BMI increased significantly in patients without cardiovascular disease (CVD; WMD, 0.200), whereas it decreased significantly in those with CVD at baseline (WMD, -0.188; between-group P value < 0.001). Moreover, the BMI increased significantly in patients with dysglycemia (WMD, 0.499) but did not increase in those without dysglycemia at baseline (WMD, 0.100; between-group P value = 0.032). Meta-regression confirmed the subgroup findings. Conclusions: The BMI increased significantly in patients with OSA after CPAP treatment, especially in those with CPAP use of ⩽5 h/night, without CVD and/or with dysglycemia at baseline. CPAP use of at least 5 h/night seems to be necessary in mitigating the risk for weight gain in patients with OSA.