Effect of Metformin on Testosterone Levels in Male Patients With Type 2 Diabetes Mellitus Treated With Insulin
Tingting Cai, Yun Hu, Bo Ding, Rengna Yan, Bingli Liu, Ling Cai, Ting Jing, Lanlan Jiang, Xiaojing Xie, Yuming Wang, Huiying Wang, Yunting Zhou, Ke He, Lan Xu, Liang Chen, Cheng Cheng, Jianhua Ma
Abstract
Aim: To explore the chronic effects of metformin on testosterone levels in men with type 2 diabetes mellitus (T2DM). Methods: 3-month intermittent flash glucose monitoring. Male patients aged 18-60 who were using metformin during the 3-month study period were included as the metformin group. The control group included males without metformin therapy by propensity score matching analysis with age as a covariate. Testosterone levels were measured at baseline and after 3-month treatment. Results: After 3-month treatment, the control group had higher levels of total testosterone, free and bioavailable testosterone than those at baseline (P<0.05). Compared with the control group, the change of total (-0.82 ± 0.59 vs. 0.99 ± 0.59 nmol/L) and bioavailable (-0.13 ± 0.16 vs. 0.36 ± 0.16 nmol/L) testosterone levels in the metformin group significantly decreased (P=0.036 and 0.029, respectively). In Glycated Albumin (GA) improved subgroup, the TT, FT, and Bio-T levels in the control subgroup were higher than their baseline levels (P < 0.05). Compared with the metformin subgroup, TT level in the control subgroup also increased significantly (P=0.044). In GA unimproved subgroup, the change of TT level in the metformin subgroup was significantly lower than that in the control subgroup (P=0.040). Conclusion: In men with T2DM, 3-month metformin therapy can reduce testosterone levels, and counteract the testosterone elevation that accompanied with the improvement of blood glucose. Clinical Trial Registration: https://www.clinicaltrials.gov/ct2/show/NCT04847219?term=04847219&draw=2&rank=1.