Lean tissue mass and energy expenditure are retained in hypogonadal men with spinal cord injury after discontinuation of testosterone replacement therapy

Objective: To determine whether favorable changes to lean tissue mass (LTM), resting energy expenditure (REE), and testosterone (T) that occurred with 12 months of physiological testosterone replacement therapy (TRT) were retained 6 months after discontinuing treatment. Design: Prospective, open-label, controlled drug intervention trial. Setting: Metropolitan area hospitals. Subjects: Eugonadal (n = 11) and hypogonadal (n = 13) men with chronic spinal cord injury (SCI). Interventions: Hypogonadal subjects received a 5 or 10 mg transdermal T patch daily for 12 months, with adjustment of the dose to normalize the serum T concentration; TRT was discontinued after 12 months (TRT-12M) and subjects were followed for an additional 6 months and re-evaluated (Post-TRT). Total body dual energy X-ray absorptiometry and blood draws were performed at baseline (BL) prior to TRT, TRT-12M, and Post-TRT. Eugonadal subjects did not receive treatment and were evaluated at comparable time points. Results: There were no significant differences between groups prior to TRT at BL for any of the study endpoints. In the hypogonadal group, a significant increase in LTM was observed from BL to TRT-12M (50.2 +/- 7.4 vs. 52.9 +/- 6.8 kg, P < 0.01), which persisted Post-TRT compared to BL (52.2 +/- 7.8 kg, P < 0.05). The increase in REE from BL to TRT-12M (1283 +/- 246 vs. 1410 +/- 250 kcal/day) was also retained at Post-TRT (1393 +/- 220 kcal/day). These sustained improvements in LTM and REE after termination of anabolic hormonal therapy may be associated with persistent beneficial effects on health and physical function of hypogonadal men with chronic SCI.