OBJECTIVE Testosterone deficiency is associated with significant morbidity, and androgen replacement in overt hypogonadism is clearly beneficial. However, there are few data concerning the response to therapy in young men with mild testosterone deficiency.
DESIGN AND PATIENTS We have identified a cohort of 35 men, mean age 40·9 years, with mild Leydig cell dysfunction, defined by a raised LH level (LH ≥ 8 IU/l) and a testosterone level in the lower half of the normal range or frankly subnormal (testosterone < 20 nmol/l), following treatment with cytotoxic chemotherapy for malignancy. Patients were assigned randomly to 12 months treatment with transdermal testosterone (n = 16) (Andropatch 2·5 mg patches, 1–2 patches per day) or placebo patches (n = 19) in a single blinded manner.
MEASUREMENTS Measurements of bone mineral density (BMD) and body composition were performed at baseline, 6 months and 12 months using single and dual energy X-ray absorptiometry (SXA, DXA). In addition, spinal BMD was assessed at baseline and 12 months by quantitative CT (QCT). Subjects were reviewed at 3-monthly intervals; at each visit blood was taken for measurement of testosterone, SHBG, LH, FSH, oestradiol, lipids and IGF-1 and patients completed three questionnaires which assessed energy levels, mood and sexual function.
RESULTS Total testosterone and calculated free testosterone increased significantly in the testosterone-treated group compared with the placebo-treated group (13·3 nmol/l and 342·9 pmol/l at baseline compared with 17·3 nmol/l and 454·8 pmol/l during the study period in the testosterone-treated group; P = 0·05 and P = 0·02, respectively). LH was suppressed into the normal range in 15 of the 16 testosterone-treated men and mean LH significantly reduced from 11·1 IU/l at baseline to 6·8 IU/l during the study. There was no significant change in BMD at the hip, spine or forearm and no change in fat or lean body mass. There was a significant reduction in physical fatigue in the testosterone-treated group compared with the placebo-treated group (P = 0·008) and a borderline improvement in activity score (P = 0·05). There were no significant effects of treatment on mood or sexual function. Neither oestradiol nor IGF-1 levels differed between the two groups during the study. There was no significant change in mean total cholesterol, HDL cholesterol or triglyceride levels, but there was a small, but significant reduction in LDL cholesterol levels in the testosterone-treated group compared with the placebo group (P = 0·02).
CONCLUSIONS These results suggest that testosterone therapy in young men with raised LH levels and low/normal testosterone levels does not result in significant changes in BMD, body composition, lipids or quality of life, apart from a reduction in physical fatigue and a small reduction in LDL cholesterol. This implies that mild hypogonadism defined on this basis is not of clinical importance in the majority of men, and that androgen replacement cannot be recommended for routine use in these patients.