Endocrine Abstracts

Background

Effects of testosterone therapy (TTh) on lipid parameters are inconsistent and may depend on treatment duration, route of administration, and adherence. While in short-term studies, testosterone usually lowers HDL, long-term studies seem to increase HDL. Total cholesterol, LDL and triglycerides are either reduced by TTh, or effects are neutral.

Material and methods

After excluding men with primary hypogonadism, 723 men with functional, symptomatic hypogonadism were either overweight or obese. 367 men received testosterone undecanoate injections 1000 mg/12 weeks following an initial 6-week interval (T-group), 356 men decided against TTh and served as controls (CTRL). Measurements were performed 1–4 times a year for approximately 6.913 patient-years. The lipid accumulation product (LAP) as an indicator of metabolic syndrome was calculated according to Kahn 2005. 12-year data are reported. 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 two groups.

Results

Mean baseline age (years): 58.8 ± 5.9 (T-group), 63.1 ± 4.9 (CTRL) (P < 0.0001). Mean (median) follow-up: 9.3 ± 3.0 (10) years (T-group), 9.8 ± 2.6 (11) years (CTRL). Lipids at 12 years (mmol/l), mean±SE: Total cholesterol decreased by 2.6 ± 0.1 (T-group) and increased by 1.4 ± 0.1 in CTRL, estimated adjusted difference between groups: -4.0 [95% CI: -4.1;-3.8] (P < 0.0001 for all). HDL increased by 0.5 ± 0.0 (T-group) and decreased by 0.4 ± 0.0 (CTRL), between-group difference: 0.9 [95% CI: -0.8;-0.9] (P < 0.0001 for all). LDL decreased by 1.7 ± 0.0 (T-group) and increased by 1.0 ± 0.0 (CTRL), between-group difference: -2.8 [95% CI: -2.9;-2.6] (P < 0.0001 for all). Triglycerides decreased by 1.0 ± 0.0 (T-group) and increased by 0.7 ± 0.0 in CTRL, between-group difference: -1.7 [95% CI: -1.7;-1.6] (P < 0.0001 for all). Non-HDL decreased by 3.0 ± 0.1 (T-group) and increased by 1.8 ± 0.1 (CTRL), between-group difference: -4.8 [95% CI: -5.0;-4.6] (P < 0.0001 for all). Remnant cholesterol decreased by 1.5 ± 0.1 in the T-group and increased by 0.6 ± 0.1 in CTRL, between-group difference: -2.1 [95% CI: -2.4;-1.8] (P < 0.0001 for all). LAP (cm*mmol/l) decreased by 90.3 ± 3.6 in the T-group and increased by 60.8 ± 3.6 in CTRL, between-group difference: -151.0 [95% CI: -162.9;-139.2] (P < 0.0001 for all). 27 patients (7.4%) died in the T-group and 98 (27.5%) in CTRL (P < 0.0001). Medication adherence to testosterone was 100% as all injections were administered in the medical office and documented.

Conclusion

In men with hypogonadism and overweight or obesity, long-term TTh improves the lipid profile which may be a contributing factor to the observed reduction in mortality.