New research suggests exposure to 5α-reductase inhibitors is associated with an increased risk of developing new-onset type 2 diabetes in men with benign prostatic hyperplasia (BPH).
The population-based cohort study, published in the BMJ, used data from the UK Clinical Practice Research Datalink (CPRD) 2003-2014 and Taiwanese National Health Insurance Research Database (NHIRD) 2002-2012 to investigate the incidence of new-onset diabetes in men receiving long-term dutasteride or finasteride for BPH.
In the CPRD data, 8231 men received dutasteride, 30,774 received finasteride and 16,270 received tamsulosin. During mean follow-up of 5.2 years, there were 2081 new onset type 2 diabetes events - 368 in the dutasteride group, 1207 in the finasteride group and 506 in the tamsulosin group.
The event rate per 10,000 person years was 76.2 (95% CI, 68.4-84.0) for dutasteride, 76.6 (95% CI, 72.3-80.9) for finasteride, and 60.3 (95% CI, 55.1-65.5) for tamsulosin. There was a modest increased risk for type 2 diabetes for dutasteride (aHR, 1.32; 95% CI, 1.08-1.61) and finasteride (aHR, 1.26; 95% CI, 1.10-1.45) compared with tamsulosin.
Results for the NHIRD were consistent with the findings for the CPRD, showing increased diabetes risk with dutasteride (aHR, 1.34; 95% CI, 1.17-1.54) and finasteride (aHR, 1.49; 95% CI, 1.38-1.61).
The study authors concluded that the risk of developing new-onset type 2 diabetes appears to be higher in men exposed to 5α-reductase inhibitors than in men receiving tamsulosin, but the risk does not differ between men receiving dutasteride and those receiving finasteride.
They say additional monitoring might be required for men starting these drugs, particularly in those with other risk factors for type 2 diabetes.