Impact of CPAP treatment for obstructive sleep apnea on visceral adipose tissue: a meta-analysis of randomized controlled trials.

BACKGROUND: It is still controversial if the continuous positive airway pressure (CPAP) treatment for patients with obstructive sleep apnea (OSA) can markedly influence an effect on visceral adipose tissue (VAT). The current study aimed to assess the efficacy of CPAP interventions in reducing VAT in OSA patients. METHODS: The Web of Science, PubMed, Embase, and Cochrane Library (up to December, 2019) were searched for randomized trials that assessed the effect of CPAP therapy in decreasing VAT in OSA patients. Information on the study, pre- and post-CPAP treatment of VAT, and patient characteristics were extracted for analysis. The standardized mean difference (SMD) was applied to measure the summary estimates. The analysis was conducted with STATA 13.0 and RevMan v.5.3. RESULTS: Five studies (6 cohorts) that involved 169 patients were enrolled in the meta-analysis. There was no significant change of VAT in patients with OSA before and after CPAP treatment (SMD = - 0.00, 95% CI = - 0.21 to 0.21, z = 0.01, p = 0.99). Subgroup analyses further demonstrated that the results were not influenced by CPAP therapy duration, patient age, sample size, or baseline body mass index. CONCLUSIONS: Among the patients with OSA, our meta-analysis revealed that treatment with CPAP does not significantly lead to a reduction of VAT. High-quality randomized controlled trials may provide further clarifying information.