Lower irisin level in patients with type 2 diabetes mellitus: A case-control study and meta-analysis

Irisin is a newly identified myokine in mice and humans. Many studies have reported irisin concentrations in patients with type 2 diabetes mellitus (T2DM). The large variations in irisin concentrations in different studies may be attributable to differences in sample size or populations. The aim of the present study was to establish an accurate confidence interval of irisin levels in T2DM patients using a case-control study and large-scale meta-analysis.

Serum irisin concentrations were determined in newly diagnosed T2DM patients (n = 50) and age- and body mass index-matched controls (n = 50) in a case-control study. Further, a meta-analysis was conducted to verify whether circulating irisin concentrations are lower in patients with T2DM. All publications regarding the association between irisin and T2DM in Medline, PubMed and EMBase were retrieved using the keywords "irisin" and "myokine". Review Manager 5.0 (Cochrane Collaboration, Oxford, UK) was used to pool the data.

In the case-control study, irisin concentrations were lower in newly diagnosed T2DM patients compared with healthy controls. In the meta-analysis, the pooled data indicated that irisin concentrations were 24.46 ng/mL (95% confidence interval [CI] 9.31, 39.60; P = 0.002) lower in T2DM patients than healthy controls.

This study confirmed that circulating irisin concentrations were significantly lower in patients with T2DM.