Improvement of type 2 diabetes (T2DM) in hypogonadal men receiving long-term testosterone therapy: Real-life evidence from a 10-registry study in a urological office

Objectives: The high prevalence of hypogonadism in men with type 2 diabetes mellitus (T2DM) is well established. We studied effects of testosterone therapy (TTh) in hypogonadal men with T2DM in a urological office. All men received standard diabetes treatment by their respective specialists. Material and Methods: 133 men with T2DM, testosterone <350 ng/dL and symptoms of hypogonadism received testosterone undecanoate 1000 mg every 3 months following an initial 6-week interval for up to 10 years. 153 hypogonadal men with T2DM opted against TTh and served as controls. Measurements were performed 1-4 times a year and included fasting glucose, HbA1c, insulin, and HOMA-IR. Differences between groups were estimated and adjusted for age and metabolic syndrome parameters to account for baseline differences between groups. Results: Mean age: 63±5 years (T-group: 62±5, CTRL: 64±5). Fasting glucose decreased from 7.6±1.1 to 5.3±0.1 mmol/L in the T-group. In CTRL, fasting glucose increased from 6.2±0.6 to 6.9±1.0 mmol/L, estimated adjusted difference between groups:-2.2 mmol/L (p<0.0001 for all). HbA1c decreased from 8.8±0.9 to 5.9±0.3% at 10 years in the T-group. In CTRL, mean HbA1c increased from 7.7±0.6 to 9.5±0.9%, estimated adjusted difference between groups:-4.6% (p<0.0001 for all). Fasting insulin decreased from 29.6±4.2 to 15±4.8 juU/mL. In CTRL, fasting insulin increased from 26.5±2.6 to 37 juU/mL, estimated adjusted difference between groups:-23.1 juU/mL (p<0.0001 for all). HOMA-IR decreased from 10.2±2.0 to 3.6±1.2 at 10 years. In CTRL, HOMA-IR increased from 7.4±1.4 to 11.4, estimated adjusted difference between groups:-9.4 mmol/L (p<0.0001 for all). At baseline, 54 patients in the T-group received insulin at a mean dose of 32.4±12.1 units/day. Mean dose requirement declined to 20.6±11.3 units. In CTRL, 55 patients received insulin at a mean dose of 29.4±5 units/day with an increase of mean dose requirement to 39.5±7.2 units, estimated adjusted difference between groups:-25.7 units/day (p<0.0001). Conclusions: T2DM improved sustainably under long-term TTh and progressed in untreated hypogonadal controls. Testosterone should be measured routinely and TTh offered to men with T2DM when indicated.