No elevation of serum adiponectin in OSA patients after continuous positive airway pressure treatment: a meta-analysis

It is reported that the level of serum adiponectin is closely associated with status of obstructive sleep apnea (OSA). However, the effect of continuous positive airway pressure (CPAP) on adiponectin concentration remains controversial. Therefore, the aim of study is to testify the hypothesis that there is a systematic elevation in serum adiponectin with CPAP. We reviewed relevant studies by searching Medline, Pubmed, Embase, and the Cochrane library from 2006 to 2014. Eligible studies which focused on effects of CPAP on adiponectin levels in OSA patients, were identified by two independent reviewers. RevMan and STATA software were utilized for data synthesis and analysis. Association between CPAP and adiponectin was evaluated by polled analysis, and subgroup analysis, basing on detection method, duration of CPAP, sample size, body mass index (BMI), apnea hypopnea index and regional distribution. In total 10 articles were enrolled into the meta-analysis. The results demonstrated that standardised mean difference of the adiponectin levels pre- and post-CPAP therapy was -0.04 (95 % CI -0.21 to 0.12), test for overall effect z = 0.49 (P = 0.62). Subgroup analysis showed that differences in detection method, duration of CPAP, sample size, BMI, OSA severity and regional distribution did not affect the results of polled analysis. The study demonstrated that there was no systematic change in serum adiponectin with CPAP in OSA patients.