Introduction: Testosterone deficiency is a prevalent condition in men with chronic kidney disease. We investigated effects of testosterone therapy on renal parameters and renal function in men with functional hypogonadism. Methods: 898 men with hypogonadism, 481 men chose TTh by means of testosterone undecanoate (TU) injections 1000 mg/12 weeks following an initial 6-week interval (T-group). 417 men opted against TTh and served as controls (CTRL). 14-year data are presented. Changes over time between groups were compared and adjusted for age, weight, waist circumference, fasting glucose, blood pressure, lipids and quality of life to account for baseline differences between the groups. Means and standard deviations of absolute measures over 14 years are reported. eGFR was calculated using the Modification of Diet in Renal Disease (MDRD) formula. Results: Baseline age was 56.5±8.0 years in the T-group and 62.7±5.3 years in CTRL (p < 0.0001). Mean follow-up was 11.0±3.2 years in the T-group and 11.1±3.3 in CTRL. Median follow-up was 12 years in the T-group and 12 years in CTRL. Creatinine (mg/dL) decreased by 0.10±0.03 at 14 years in the T-group (p < 0.005) and increased by 0.33±0.04 in CTRL (p < 0.0001). Estimated adjusted difference between groups at 14 years was -0.50 [95% CI: -0.58;-0.41] (p < 0.0001). ?GT (U/L) decreased by 24.0±0.7 at 14 years in the T-group and increased by 26.2±0.8 in CTRL, estimated adjusted difference between groups at 14 years: -47.3 [95% CI: -49.4;-45.1] (p < 0.0001 for all). eGFR-(MDRD) (mL/min/1.73 m²) increased by 10.3±0.7 in T-group, reaching a peak in year 8 with a small but steady decline thereafter. eGFR-MDRD decreased progressively by 27.3±0.8 in CTRL. Estimated adjusted difference between groups at year 14: 41.5 [95% CI: 39.5;43.6] (p < 0.0001 for all). Systolic blood pressure (mmHg) decreased in the T-group by 23.5±0.7 and increased in CTRL by 21.6±0.8. Estimated adjusted difference between groups: -38.1 [95% CI: -40.2;-35.9] (p < 0.0001 for all). Diastolic blood pressure (mmHg) decreased by 14.7±0.5 (T-group) and increased by 14.3±0.5 (CTRL). Estimated adjusted difference between groups: -25.0 [95% CI: -26.5;-23.6] (p < 0.0001 for all). During the entire observation period, 49 deaths (10,2%) occurred in the T-group. In CTRL, 133 deaths (31.9%) were recorded. All injections were administered in the office and documented. Conclusions: Long-term testosterone therapy in men with hypogonadism improves renal function demonstrated by eGFR, potentially contributing to reduced mortality. SOURCE OF Funding: Data entry was compensated by Bayer AG.
