Association between testosterone with type 2 diabetes in adult males, a meta-analysis and trial sequential analysis

We performed this meta-analysis to assess serum testosterone changes in adult males with Type 2 diabetes (T2DM). PubMed, Embase, Web of Science, and Cochrane Library were searched to identify qualified studies. Pooled weighted mean differences (WMDs) with 95% confidence intervals (CIs) were utilized to test the changes of total testosterone (TT), free testosterone (FT) and sex hormone-binding globulin (SHBG) in patients with T2DM. Besides, trial sequential analysis was used to verify the pooled results. A total of 56 studies were enrolled in our meta-analysis. Meta-analyses of the cross-sectional studies showed that patients with T2DM has significant decreases in TT (WMD: −2.98, 95%CI: −3.48 to −2.47), FT (WMD: −32.82, 95%CI: −39.70 to −25.95) and SHBG (WMD: −2.47, 95%CI: −3.93 to −1.02). In terms of the prospective studies, our results showed decreases in TT (WMD: −2.35, 95%CI: −3.24 to −1.46), FT (WMD: −25.96, 95%CI: −83.98 to 32.05), and SHBG (WMD: −10.06, 95%CI: −13.29 to −6.84) in patients with T2DM. By trial sequential analyses, the findings in current meta-analysis were based on reliable evidence. Our results indicate that patients with T2DM have lower serum TT, FT, and SHBG levels.