Endocrine Abstracts

Context: Testosterone replacement therapy (TRT) has shown benefit on insulin resistance, glycaemic control and cardiovascular risk markers in hypogonadal men with diabetes. Arterial stiffness and intima-media thickness (IMT) are vessel wall properties associated with future cardovascular risk which allow the progress of atherosclerosis to be assessed non-invasively. Low testosterone has been associated with the presence and progression of carotid atherosclerosis as assessed by IMT.

Methods: Double-blind placebo controlled parallel group study of 24 hypogonadal men with insulin treated type 2 diabetes examining the effect of TRT on ultrasound assessed markers of atherosclerosis. Participants were randomised to i.m. testosterone (n=11) or placebo (n=13) every 2 weeks for 6 months. Carotid artery stiffness (stiffness index beta) and IMT were assessed by ultrasound at baseline, 3 and 6 months. Other assessments included conventional cardiovascular risk markers and hypogonadal symptoms (AMS score).

Results: The testosterone and placebo groups did not significantly differ at baseline, 3 or 6 months in terms of arterial stiffness, IMT, HbA1c, anthropomorphics, blood pressure, lipids, PSA or AMS score. Testosterone was associated with an increase in haematocrit (+0.034 vs −0.006, P=0.003) but no patient developed a raised haematocrit. One patient in the placebo group withdrew from the trial after foot ulceration worsened. There were no significant adverse events in the testosterone group.

Conclusion: TRT given to men with insulin treated type 2 diabetes had no effect on ultrasound assessed atherosclerosis and we failed to confirm the beneficial effects of testosterone on weight, glycaemic control and lipid parameters seen in other trials. The trial was underpowered to draw strong conclusions from these negative results. Additional reasons that the study failed to demonstrate the effects of testosterone may have been an advanced state of atherosclerosis and insulin resistance at baseline and the short duration of the study.