SAT-533 Men with Hypogonadism and Osteoporosis Benefit from Long-Term Testosterone Therapy (TTh) with Testosterone Undecanoate Injections (TU) Regardless of Co-Medication with Bisphosphonates: 10-Year Data from a Controlled Registry Study in a Urological Setting

Abstract

Background: Testosterone and its metabolite estradiol are essential factors in bone metabolism, and hypogonadism is an established risk factor for osteoporosis. Material and Methods: In a registry study of otherwise unselected men with hypogonadism in a urological office, 102 of 805 patients (13%) had osteoporosis diagnosed and treated elsewhere. 69 received TTh with TU 1000 mg/12 weeks (T-group). 33 had opted against TTh and served as controls (CTRL). BMD was measured at least once a year by using a whole body dual-energy X-ray densitometer (Norland XR-800). 10-year data are reported. Changes over time between groups were compared by mixed effects model for repeated measures with random effect for intercept and fixed effects for time, group and their interaction, and adjusted for age, weight, waist circumference, fasting glucose, blood pressure and lipids to account for baseline differences between groups. Results: Baseline age: 54.5±8.2 (T-group), 64.9±4.1 years (CTRL). Mean (median) follow-up was 7.5±2.3 (8) years in the T-group and 8.9±1.1 (9) years in CTRL. 36 (52%) in the T-group had Klinefelter’s syndrome (KS) which, in the majority of cases, was diagnosed secondary to the diagnosis of osteoporosis. 7 patients had primary hypogonadism other than KS, 6 had a history of alcohol abuse, 4 had Crohn’s disease, and 3 had had a kidney transplant. All patients were on Vitamin D-calcium supplements. 64 patients (93%) in the T-group and 23 (70%) in CTRL were on bisphosphonates at baseline. 11 patients (16%) in the T-group and 11 (33%) in CTRL discontinued bisphosphonates due to side effects. T-scores progressively improved from -3.39±0.56 to -1.19±0.03 after 10 years (T-group) and worsened from -3.01±0.3 to -3.83±0.53 in CTRL, adjusted difference between groups: 2.45 (p<0.0001 for all). At the last measurement, 64 patients (93%) in the T-group had osteopenia; only 5 with a maximum treatment duration of 42 months still had osteoporosis. In CTRL, no patient achieved osteopenia. There were 6 fractures in CTRL but none in the T-group. Adherence to TTh was 100 per cent as all injections were administered in the doctor’s office and documented. Conclusion: Long-term TTh with TU in an unselected cohort of hypogonadal men with osteoporosis resulted in sustained improvements in T-scores with a high proportion of resolution of osteoporosis which depended on duration of TTh. In untreated controls, T-scores worsened and fractures occurred. Bisphosphonate treatment did not result in any improvement of bone density in the untreated hypogonadal controls.