Increase in deaths in men with type 2 diabetes and testosterone deficiency may be prevented by testosterone replacement, study suggests

Professor Jones' team conducted a six year study of 587 men with type 2 diabetes, splitting them into three groups: those with normal total testosterone levels (above 10.4nmol/L, n=338), those with low testosterone levels (below 10.4nmol/L) that weren't treated with testosterone replacement therapy (n=182), and those with low testosterone levels treated with testosterone replacement therapy for two years or more during the follow up period (n=58).

The findings show for the first time that low testosterone puts diabetic men at a significantly increased risk of death (p=0.001 log rank): 36 of the 182 diabetic men with untreated low testosterone died during the six year study, compared to 31 of the 338 men with normal testosterone levels (20% vs 9%). Furthermore, only 5 of the 58 diabetic men that were given testosterone replacement therapy died during the study (8.6%), meaning they showed significantly better survival compared to the non-treated group (p=0.049 log rank).

This is the first study to show testosterone treatment can improve survival in men with type 2 diabetes and testosterone deficiency. Further studies now need to be carried out to fully investigate the potential therapeutic benefit of testosterone replacement in diabetic men with low testosterone.

Professor Hugh Jones, Consultant Endocrinologist and Hon. Professor of Andrology, Barnsley Hospital NHS Foundation Trust and the University of Sheffield, said: "This is potentially a very exciting finding. Whilst we have shown that low testosterone levels can put diabetic men at greater risk of dying, we have also demonstrated for the first time the potential benefit that testosterone replacement therapy holds for this group of patients.

"It is well known that men with type 2 diabetes often have low testosterone levels, so it is important that we investigate the health implications of this. We now need to carry out a larger clinical trial to confirm these preliminary findings. If confirmed, then many deaths could be prevented every year."

In another study, also presented at this year's Society for Endocrinology meeting, Professor Jones' group found for the first time that low testosterone and severity of erectile dysfunction are independently associated with a reduced health-related quality of life in men with type 2 diabetes. Health-related quality of life questionnaires, such as the one used in this study, measure how a person perceives their own general health in areas such as physical and social functioning, vitality and pain. The questionnaire does not measure how good a person's health actually is; it measures how good a person thinks their health is in daily life.

In the 356 men with type 2 diabetes tested, health related quality of life decreased as testosterone levels decreased (r=0.353 p=0.044). In the 126 patients who were also assessed for erectile dysfunction, health-related quality of life decreased in the areas including physical functioning (r=0.5, p=0.003), social functioning (r=0.445, p=0.022) vitality (r=0.383, p=0.025) and pain (r=0.428, p=0.012) as the severity of erectile dysfunction increased. Although severity of erectile dysfunction has been shown to be associated with lower testosterone levels, statistical analysis shows for the first time that these are both independently associated with a reduced health-related quality of life in these men.

Lead researcher Prof Hugh Jones said: "Our research shows that low testosterone impacts on health-related quality of life in men with type 2 diabetes. This finding supports previous evidence suggesting that erectile dysfunction is a marker of ill health.

"Our next step is to assess whether offering testosterone replacement therapy to diabetic men with testosterone deficiency and erectile dysfunction may help to improve their health related quality of life."