Bone mineral density outcomes following long-term treatment with subcutaneous testosterone pellet implants in male hypogonadism.

BACKGROUND Osteoporosis is a common complication of untreated male hypogonadism. Even mild hypogonadism due to suboptimal testosterone replacement may result in decreased bone mineralization and osteoporosis. OBJECTIVE To assess bone mineral density in hypogonadal men following long-term long-acting subcutaneous testosterone pellet implants as replacement therapy. PATIENTS A cross-sectional study of 37 patients with primary or secondary hypogonadism receiving long-term (mean 6.6 years) subcutaneous testosterone pellet implants as replacement therapy. MEASUREMENTS Bone mineral density was measured in all patients using dual energy X-ray absorptiometry. Serum testosterone 3-4 months after insertion of pellets was measured in all patients to assess adequacy of replacement therapy. RESULTS Mean areal bone mineral density were 1.02 (SD 0.14) g/cm2 with a mean Z score of -0.64 (SD 1.3) and 0.87 (SD 0.13) g/cm2 with a mean Z score of -0.72 (SD 1.2) at lumbar spine and neck of femur, respectively. Mean serum testosterone 3-4 months after pellets insertion was 15.45 nmol/l (SD 4.2 nmol/l). There was no significant correlation between bone mineral density and patient's age at start or duration of testosterone therapy. CONCLUSIONS Bone mineral density in long-term regularly treated hypogonadal men was not different from the age-matched reference range for normal men. Long-acting subcutaneous testosterone pellet implants as replacement therapy in male hypogonadism are safe, acceptable to the patient, result in adequate bone mass accumulation and maintenance of normal bone mineral density. By provision of sustained physiological levels of testosterone they may contribute to increased androgen effect at the receptor level.