Endocrine Abstracts

Introduction: type 2 diabetes mellitus (T2DM) and hypogonadism are common conditions afflicting the aging male, often present together. The specific role of testosterone (T) replacement therapy (TRT) on glycometabolic profile and body composition, particularly in patients with T2DM, is still the object of an intense debate. The aim of the present study is to meta-analyze the role of TRT in T2DM considering all placebo and non-placebo-controlled randomized clinical trials (RCTs).

Methods: an extensive Medline, Embase and Cochrane search was performed. We did not employ search software but hand-searched bibliographies of retrieved papers for additional references. All RCTs studies investigating the impact of TRT on glycometabolic outcomes without any restriction were included.

Results: overall, 12 studies were available including 684 patients with a mean follow-up of 38.4 weeks. These trials differ in basal TT levels and type of T preparation used. In addition, only 10 were placebo controlled Patients with impaired fasting glucose were characterized by a 3 nmol/l lower level of total testosterone when compared to controls. Similarly, impaired fasting glucose was associated with a 1.8-fold increased risk of hypogonadism, when compared to subjects with normal glucose levels. Secondary hypogonadism was two times higher in subjects with impaired fasting glucose when compared to rates observed in the general population. Testosterone replacement therapy was able to improve body composition, insulin resistance, and glucose profile both in impaired fasting glucose and type 2 diabetes mellitus whereas its role on body weight, lipid profile, and sexual function was less evident.

Conclusions: The overall data analysis indicates that TRT favorably affects glycemic control in diabetic subjects reducing fasting glycaemia, HbA1c and HOMA index and decreasing triglyceride levels and fat mass. All these differences were confirmed when only placebo-controlled studies were evaluated, with the exception for HbA1c decrease, where only a trend towards a decrease was apparent. Conversely no effects on TRT on erectile function was observed.