Serum Irisin and Diabetic Nephropathy in Patients with Diabetes Mellitus

Dear Editor, I read the article by Wang et al., who conducted a meta-analysis to investigate the association between serum irisin levels and diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM) 1. The mean serum irisin level in T2DM patients with microalbuminuria was significantly lower than that in T2DM patients with normoalbuminuria. In addition, the mean serum irisin level in T2DM patients with macroalbuminuria was significantly lower than that in T2DM patients with microalbuminuria. Furthermore, the mean serum irisin level in T2DM patients with estimated glomerular infiltration rate (eGFR)<60 ml/min 1.73 m2 was significantly lower than that in T2DM patients with eGFR≥60 ml/min 1.73 m2. The authors concluded that decreased serum irisin level was associated with albuminuria and reduced eGFR in T2DM patients. DN was significantly related to decreased serum irisin level in T2DM patients with dose-response manner. Progression of DN may be considered as advanced DM status, and serum irisin level would reflect glucose intolerance via insulin resistance. I have a comment about their study with special reference to the fundamental relationship between the types of DM and serum irisin levels.