medwireNews: Men with benign prostatic hyperplasia undergoing long-term treatment with 5α-reductase inhibitors are significantly more likely to develop type 2 diabetes than those receiving the α-blocker tamsulosin, population-based study data show.
The risk, however, did not differ between men receiving dutasteride and finasteride, two commonly used 5α-reductase inhibitors, report Ruth Andrew (University of Edinburgh, UK) and co-authors in The BMJ.
They suggest: “The decision to prescribe steroid 5α-reductase inhibitors for men with metabolic disease should be made in the context of other risk factors for type 2 diabetes; additional monitoring of blood glucose might be advisable.”
The study included 55,275 men from the UK Clinical Practice Research Datalink who received at least two prescriptions of dutasteride (n=8231), finasteride (n=30,774), or tamsulosin (n=16,270) between 2003 and 2014.
During a mean 5.2 years of follow-up, there were 2081 cases of type 2 diabetes diagnosed, with event rates of 76.2, 76.6, and 60.3 per 10,000 person–years for dutasteride, finasteride, and tamsulosin, respectively.
After adjustment for a number of potential confounders, including benign prostatic hyperplasia duration and concomitant use of corticosteroids and cardiovascular drugs, the researchers found that there were “modest” but significant increased risks for type 2 diabetes with dutasteride and finasteride compared with tamsulosin, at adjusted hazard ratios (aHR) of 1.32 and 1.26, respectively.
Propensity score matching attenuated the risk associated with finasteride to a nonsignificant aHR of 1.22, but it remained significant for dutasteride, at 1.34. There was no significant difference in risk between the people prescribed dutasteride and those prescribed finasteride.
Furthermore, Andrew and team replicated the findings in a cohort of 91,708 patients from the Taiwanese National Health Insurance Research Database.
In this group, the event rates were 152.8, 109.1, and 74.7 per 10,000 person–years for dutasteride, finasteride, and tamsulosin, respectively, during a mean 3.1 years of follow-up, and compared with tamsulosin the aHRs for developing type 2 diabetes were a significant 1.34 with dutasteride and a significant 1.49 with finasteride.
Propensity score matching slightly attenuated the risk associated with dutasteride (aHR=1.18) but increased that associated with finasteride (aHR=1.61).
The researchers say that their findings “are comparable to the increased incidence of type 2 diabetes with statin use,” and although the risk increase they identified was “modest,” it was “consistent between the two study populations.”
They conclude: “This study should alert clinicians that patients starting 5α-reductase inhibitor treatment might benefit from early lifestyle advice and monitoring of type 2 diabetes.”
By Laura Cowen
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