Testosterone Treatment and Sexual Function in Men: Secondary Analysis of the T4DM (Testosterone for Diabetes) Trial

Abstract

Context The combined effects of testosterone treatment and lifestyle intervention on sexual function in men at high risk of type 2 diabetes are unclear. Objective To assess the effect of testosterone treatment with a lifestyle intervention in men aged 50 to 74 years at high risk of, or newly diagnosed with, type 2 diabetes (via oral glucose tolerance test). Design A secondary analysis of the Testosterone for the Prevention of Type 2 Diabetes trial, a double-blind, placebo-controlled trial conducted across 6 Australian centers. Interventions Intramuscular testosterone undecanoate (1000 mg) or placebo, 3 monthly for 2 years alongside a community-based lifestyle program. Main outcomes Sexual function measured using the International Index of Erectile Function (IIEF)-15 questionnaire. Results Of 1007 participants, 792 (79%) had complete International Index of Erectile Function-15 data. Baseline domain scores were inversely related to age and waist circumference, but unrelated to serum testosterone or estradiol levels. Testosterone treatment improved all 5 International Index of Erectile Function-15 domain scores, with stronger effects on sexual desire and orgasmic function in older men, and sexual desire in men with higher depression scores. Testosterone had no impact on depression. Independent of treatment, reductions in waist circumference were associated with improved erectile function, and reductions in depression scores correlated with better sexual function. Clinically significant improvement in erectile function and sexual desire occurred in 3% and 10% of men, respectively, and was inversely related to baseline function. Clinically significant improvement improvements in erectile function and sexual desire were greater in younger and older men respectively. Conclusion Testosterone treatment enhanced sexual desire and, to a lesser extent, erectile function, particularly in older men and those with higher waist circumference or depressive symptoms. Reduced waist circumference and depression independently improved sexual function.