Study: Long-term Testosterone Replacement in Men with Type 2 Diabetes Improves Survival

Written by Kamiah A. Walker
Reviewed by EndocrineWeb Editorial Board

It’s known that low testosterone levels in men are associated with increased mortality.  It’s also known that men with type 2 diabetes have a high prevalence of testosterone deficiency.  Previously, it’s been shown that there is an increased mortality in men with type 2 diabetes and low testosterone, but there hasn’t been any long-term data published on the effect of testosterone replacement (TRT) in men with type 2 diabetes and hypogonadism.

Therefore, a group of researchers from the United Kingdom wanted to examine the effect of TRT in hypogonadal men with type 2 diabetes on all-cause mortality.  They presented their results at the 2011 Endocrine Society Annual Meeting in a study called “Long-Term Testosterone Replacement Improves Survival in Men with Type 2 Diabetes and Hypogonadism.”

This was a 6-year follow-up study.  There were 585 patients (mean age: 59.45, SD 10.8) with type 2 diabetes, and they had testosterone levels tested between 2002 and 2005.  They were followed-up for a mean period of 5.8 years (SD 1.3).

Patients were analyzed in 3 groups (after excluding for death in the first 6 months, n=4).  The three groups were:

Out of the 581 patients who were analyzed, 343 (59% had TT levels of >10.4 nmol/L and 238 (41%) had low TT.

The mean duration of TRT was 41.6 months (SD+20.7).  There were 60 patients who received TRT for >12 months; 51 of those had TRT for >2 years.

Compared to the normal TT group, those in the low TT group were more likely to have poor diabetes control (A1c 7.5±1.3 for the low TT group; A1c 7.1±1.4 for the normal TT group, p=0.002).  The low TT group was also more likely to have a higher weight (102±21.5 vs. 95.3±18.4, p<0.0001) than the normal TT group.

The low TT groups (treated and non-treated) were equally matched for age, weight, A1c, smoking status, pre-existing cardiovascular disease, statin, and ACEi/ARB use. 

There were 72 deaths (12.4%), and the mortality rate was the highest in the low TT group without treatment.  For that group, 33 out of 182 patients died (19.2%).  This is compared to the normal TT group:  31 out of 343 patients died in that group (9%).  The death rate was lowest in the TRT group:  5 out of 60 patients (8.3%).

The survival rate was significantly decreased for patients in the low TT group without treatment (p=0.001 log rank) when compared to the normal TT group.

A Cox Regression model was used, and with it, the multivariate adjusted hazard ratio was 2.2 (CI 95%; 1.3-3.7, p=0.001) for the low TT group without treatment.

The low TT group with treatment had an improved mean survival of 86.2 months (SE 1.6); this is compared to the mean survival in the low TT group without treatment—83.8 months (SE 1.8, p=0.048 log rank).

This study showed that long-term TRT in hypogonadal men with type 2 diabetes improves survival.



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