Association between continuous positive airway pressure and changes in serum leptin in patients with obstructive sleep apnoea: a meta-analysis

The role of leptin in the development of obstructive sleep apnoea (OSA) has been identified. However, the effects of OSA treatment using continuous positive airway pressure (CPAP) on serum leptin levels remain controversial. To address this issue, a meta-analysis was conducted to evaluate the effects of CPAP therapy on serum leptin levels in OSA. A comprehensive literature search was performed to identify studies that focused on the effects of CPAP therapy (treatment duration, a parts per thousand yen4 weeks) on the serum leptin levels of OSA patients. Standardised mean difference (SMD) was used to analyse the summary estimates for CPAP therapy. Fifteen studies involving 427 patients were included in the meta-analysis. Results indicate that the overall SMD of the leptin levels before and after CPAP therapy was 0.137 (95 % confidence interval (CI) 0.002 to 0.272); test for overall effect z = 1.99 (P = 0.046). Sources of heterogeneity were not found by subgroup and meta-regression analyses. Subgroup analyses showed that differences in OSA severity, baseline body mass index, compliance, CPAP duration and leptin assay did not affect the effectiveness of CPAP therapy. The evidence for the use of CPAP therapy on decrease of leptin levels in OSA patients is low, and stronger evidence is needed.