Testosterone may improve T2D, induce weight loss in hypogonadal men
Long-term therapy with testosterone undecanoate (TU) in hypogonadal men with type 2 diabetes (T2D) may improve glycaemic control and reverse disease progression, as well as induce significant weight loss, according to a study presented at EASD 2018.
Of the 805 hypogonadal men (total testosterone ≤12.1 nmol/L) enrolled in the study, 311 with T2D continued to participate in the 10-year follow-up study. Of these, 141 (mean age 61.8 years, 61 insulin-dependent) received TU injections 1,000 mg every 12 weeks while 170 (mean age 63.5 years) did not receive treatment (control group). [EASD 2018, abstract 675]
At 10 years, average fasting glucose among TU recipients decreased from 7.7 to 5.3 mmol/L, whereas for the control group, this increased from 6.3 to 8.2 mmol/L. Blood glucose control was also better in the TU arm, with a mean HbA1c reduction from 9.0 percent to 5.9 percent as opposed to an increase observed among controls (from 7.8 percent to 10.6 percent).
Moreover, 80.1 percent of TU recipients achieved the HbA1c target of <6.5 percent, while approximately 91 percent achieved HbA1c <7.0 percent at the time of last measurement. These findings show that majority of TU recipients achieved the target HbA1c levels as opposed to non-TU recipients who did not achieve both targets and, in fact, had increased HbA1c, noted the researchers.
Furthermore, TU recipients who were insulin-dependent were able to reduce their dose from an average of 34 to 20 units per day. In contrast, the control group saw an average insulin dose increase from 31 to 42 units per day.
TU recipients also had significant reductions in weight (from 113.4 to 90.7 kg; p<0.0001) and waist circumference (from 112.6 to 99.6 cm; p<0.0001) vs non-TU recipients at 10 years.
Patient adherence was 100 percent throughout the study period, as all injections were administered in-office and well documented. Sixteen TU recipients went into remission.
Overall, the findings demonstrate that long-term testosterone therapy can support diabetes treatment among hypogonadal men with T2D, said the researchers. “[The] significant weight and waist size [reductions] could have [also] contributed to the observed effects,” they added.
The downsides of testosterone
However, one issue with testosterone therapy especially among middle-aged and elderly men is its potential to induce prostate cancer, noted the researchers. Nonetheless, European and American urology guidelines agree that there is no evidence that can validate this assumption, they added. “In fact, in the present study, the incidence of prostate cancer was twice as high [among] untreated [vs] testosterone-treated patients.”
Another notable concern is the increase in haemoglobin and haematocrit which, according to the researchers, could be beneficial rather than detrimental. “Testosterone effectively treats anaemia which is not so rare in an elderly population, and anaemia itself presents a cardiovascular risk,” explains lead author Dr Farid Saad from Berlin, Germany.
“A substantially elevated haematocrit occurred very rarely in this study and was always transient in that it returned to normal with the next measurement. There was not a single heart attack or stroke in the testosterone-treated group, events [that] one may associate with an increase in haematocrit,” added Saad.
Researchers plan to continue this registry study for at least another 5 years. “The results, especially in the diabetic subgroup, are becoming increasingly interesting as we had the first patients who went into remission, some after as many of 10 years of testosterone treatment.”