Adropin levels and its associations as a fat-burning hormone in patients with polycystic ovary syndrome: a correlational meta-analysis.

AIMS Adropin is a peptide hormone with potential implications in patients with polycystic ovary syndrome (PCOS). The aim of this meta-analysis was to compare the circulating (serum/plasma) and follicular fluid adropin levels between human PCOS patients and non-PCOS controls. METHODS Relevant studies were retrieved by online database and manual searching. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) were obtained by a random-effects meta-analysis. Meta-analysis of correlations was performed for the associations of adropin with anthropometric, lipid, insulin resistance and hormonal covariates. The funnel plot analysis with Begg's and Egger's tests was used for publication bias. RESULTS A total of 9 studies were included in this meta-analysis. The results indicated that the adropin levels were significantly decreased in PCOS patients as compared to non-PCOS controls (SMD = -1.87, 95% CI = -2.55 to -1.18, p < .0001). This decrease was more evident in overweight PCOS patients than their normoweight counterparts (SMD = -0.55, 95% CI = -0.80 to -0.30, p < .0001). A one-study leave-out sensitivity analysis indicated that no single study had a significant influence on the overall outcome, suggesting the robustness of this meta-analysis. There were significant associations of decreased adropin levels with the body mass index, dyslipidemia and insulin resistance in PCOS. CONCLUSION Adropin levels are significantly reduced in PCOS patients compared to controls, and this decrease was more evident in overweight PCOS patients.