Testosterone Replacement Therapy Added to Intensive Lifestyle Intervention in Older Men With Obesity and Hypogonadism

Background Obesity and hypogonadism additively contribute to frailty in older men; however, appropriate treatment remains controversial. Objective Determine whether testosterone replacement augments the effect of lifestyle therapy on physical function in older men with obesity and hypogonadism. Design Randomized, double-blind, placebo-controlled trial. Setting VA Medical Center Participants 83 older (age ≥65 years) men with obesity (body mass index ≥30 kg/m2) and persistently low am testosterone (<10.4 nmol/L) associated with frailty. Interventions Participants were randomized to lifestyle therapy (weight management and exercise training) plus either testosterone (LT+Test) or placebo (LT+Pbo) for 6 months. Outcome Measures Primary outcome was change in Physical Performance Test (PPT) score. Secondary outcomes included other frailty measures, body composition, hip bone mineral density (BMD), physical functions, hematocrit, prostate specific antigen (PSA), and sex hormones. Results PPT score increased similarly in LT+Test and LT+Pbo group (17% vs. 16%; P = 0.58). VO2peak increased more in LT+Test than LT+Pbo (23% vs. 16%; P = 0.03). Despite similar -9% weight loss, lean body mass and thigh muscle volume decreased less in LT+Test than LT+Pbo (-2% vs. -3%; P = 0.01 and -2% vs -4%; P = 0.04). Hip BMD was preserved in LT+Test compared with LT+Pbo (0.5% vs −1.1%; P = 0.003). Strength increased similarly in LT+Test and LT+Pbo (23% vs 22%; P = 0.94). Hematocrit but not PSA increased more in LT+Test than LT+Pbo (5% vs 1%; P < 0.001). Testosterone levels increased more in LT+Test than LT+Pbo (167% vs 27%; P < 0.001). Conclusion In older, obese hypogonadal men, adding testosterone for 6 months to lifestyle therapy does not further improve overall physical function. However, our findings suggest that testosterone may attenuate the weight loss–induced reduction in muscle mass and hip BMD and may further improve aerobic capacity.