Lower irisin levels in coronary artery disease: a meta-analysis.

INTRODUCTION: Irisin is a newly discovered myokine, which is involved in energy metabolism and associated with "browning" of the white adipose tissue, obesity, diabetes mellitus and metabolic syndrome. It's still uncertain that whether irisin level is associated with coronary artery disease. The purpose of this study is to explore the relationship between irisin levels and coronary artery disease.

EVIDENCE ACQUISITION: A search of PubMed, MEDLINE, Elsevier Science Direct, Springer, Web of Science and China National Knowledge Infrastructure (CNKI) for studies published from 2000 to 2017 was undertaken to identify relevant studies. Case-control studies that reported the association between irisin levels and coronary artery disease were included. Methodological quality of the studies was assessed according to the Newcastle-Ottawa Scale. Random-efforts models were used to analyze the weighted mean difference (WMD) and its 95% confidence interval (CI). Subgroup analysis was performed to explore potential sources of heterogeneity.

EVIDENCE SYNTHESIS: From 741 studies, 7 case-control studies involving 867 patients and 700 controls were selected for meta-analysis based on our inclusion and exclusion criteria. In these case-control studies, irisin concentrations were lower in coronary artery disease patients compared with healthy controls. In the meta-analysis, the pooled data indicated that irisin levels were -18.10ng/ml ([95%CI, -35.53 to -0.68ng/ml]; P<0.05) lower in patients with cardiovascular disease or atherosclerosis than healthy controls.

CONCLUSIONS: This study confirmed that irisin levels were significantly lower in patients with coronary artery disease.