Testosterone associations with erectile dysfunction, diabetes, and the metabolic syndrome

Hypogonadism and erectile dysfunction are common disorders seen in patients presenting to urology clinics. Increasing evidence indicates that both disorders have important associations with the metabolic syndrome, type 2 diabetes, and cardiovascular disease, all conditions with an increased morbidity and mortality. A low testosterone level is positively associated with the presence and severity of atherosclerosis. The early recognition of these clinical conditions is important to allow treatment and hence reduce cardiovascular risk. Recent publication of guidelines to aid the diagnosis of hypogonadism and a better understanding of how to interpret biochemical tests of androgen deficiency are helping to clarify which patients require testosterone substitution. Symptoms of hypogonadism are not specific and can be especially confounding in men with chronic diseases such as diabetes. Furthermore, convincing evidence shows that testosterone replacement, in addition to improving well-being and symptoms of hypogonadism, may have other vascular and metabolic benefits. Erectile dysfunction is associated with both diabetes and atherosclerosis. Men who fail to respond to phosphodiesterase type S inhibitors are more likely to have low testosterone levels and testosterone replacement improves the response. Testosterone substitution also can improve glycaemic control, insulin resistance, and waist circumference. in hypogonadal men with type 2 diabetes and cardiac ischaemia in angina. The role of testosterone in these conditions requires further investigation; however, the identification of hypogonadism in its own right requires treatment. Larger studies are underway to investigate the additional potential benefits of testosterone therapy in men with diabetes and metabolic syndrome.