Association Between Serum Irisin and Diabetic Nephropathy in Patients with Type 2 Diabetes Mellitus: A Meta-Analysis.

Irisin, an emerging adipokine, has been involved in the pathogenesis of type 2 diabetes mellitus (T2DM). However, previous studies evaluating the association between irisin and diabetic nephropathy (DN) showed inconsistent results. We performed a meta-analysis to evaluate the above association. Matched case-control studies evaluating the difference of serum irisin between T2DM patients with and without DN were identified via systematic search of PubMed, Embase, Cochranes' Library, China National Knowledge Infrastructure, and WanFang databases from inception to December 5, 2020. A random-effects model or a fixed-effects model was used to pool the results according to the heterogeneity. Overall, thirteen matched case-control studies including 1735 T2DM patients were included. Results of meta-analysis showed that compared to T2DM patients with normoalbuminuria, those with microalbuminuria [10 studies, standard mean difference (SMD): 1.12, 95% confidence interval (CI): 0.48-1.77, p<0.001; I=94%] and macroalbuminuria (10 studies, SMD: 1.86, 95% CI: 0.93-2.79, p<0.001; I=97%) had significantly lower serum irisin. Besides, the serum level of irisin was significantly lower in T2DM patients with macroalbuminuria than those with microalbuminuria (10 studies, SMD: 0.91, 95% CI: 0.44-1.38, p<0.001; I=90%). In addition, patients with estimated glomerular infiltration rate (eGFR)<60 ml/min 1.73 m had lower serum irisin compared to those with eGFR≥60 ml/min 1.73 m (4 studies, SMD: 0.89, 95% CI: 0.32-1.46, p=0.002; I=91%). In conclusion, serum irisin may be associated with albuminuria and reduced eGFR in T2DM patients.