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Prostate Drugs Increase Diabetes Risk

May 7, 2019
 

Author: Steve Freed, R.PH., CDE


Study results should be explained to men being treated for BPH with dutasteride or finasteride, as these prostate drugs increase diabetes risk according to researchers.

Results from a new study led by the University of Edinburgh and UCL suggests men taking medicines to reduce the symptoms of prostate disease may be more likely to develop type 2 diabetes.

Men over 50 have a 50 percent chance of having Benign prostate hypertrophy [BPH], while men over 80 have a 90 percent chance of having the condition. Current estimates show approximately two million men currently receive treatment for BPH. Symptoms of BPH vary from man to man and worsen over time as the prostate gland continues to enlarge. BPH may cause difficulty in urinating or increased frequency and urgency of urination.

An  older study published in BMJ examined the use of two similar drugs often prescribed for the condition, finasteride (Proscar) and dutasteride (Avodart), in 39,000 men. As controls, the 11-year study used 16,000 men taking tamsulosin (Flomax), a different type of drug for B.P.H.

A current study published in the British Medical Journal was funded by the Edinburgh and Lothians Health Foundation. Researchers from the Universities of Dundee and Newcastle and National Cheng Kung University in Taiwan also contributed. The study, involving 55,000 men, was carried out across 11 years and looked at how taking 5-alpha-reductase inhibitors impacted the health of all participants. They found evidence to suggest the drugs increased the risk of type 2 diabetes by a third.  Additional monitoring might be required for men starting these drugs, particularly in those with other risk factors for type 2 diabetes.

This demonstrates the importance of how routinely collected healthcare data can be used to identify significant clinical links. It is important that all patients are made aware of the risks and benefits of their medications. In this instance, men should be alerted to the increased risk of diabetes if they are taking these particular medicines for BPH and should speak to their doctor if they are concerned.

Men in the study who received dutasteride (n=8231), finasteride (n=30 774), or tamsulosin (n=16 270) were evaluated. Propensity score matching (2:1; dutasteride to finasteride or tamsulosin) produced cohorts of 2090, 3445, and 4018, respectively. In the NHIRD, initial numbers were 1251 (dutasteride), 4194 (finasteride), and 86 263 (tamsulosin), reducing to 1251, 2445, and 2502, respectively, after propensity score matching.

In this study, 2,081 new onset type 2 diabetes events (368 dutasteride, 1,207 finasteride, and 506 tamsulosin) were recorded during a mean follow-up time of 5.2 years (SD 3.1 years). The event rate per 10 000 person years was 76.2 (95% confidence interval 68.4 to 84.0) for dutasteride, 76.6 (72.3 to 80.9) for finasteride, and 60.3 (55.1 to 65.5) for tamsulosin. There was a modest increased risk of type 2 diabetes for dutasteride (adjusted hazard ratio 1.32, 95% confidence interval 1.08 to 1.61) and finasteride (1.26, 1.10 to 1.45) compared with tamsulosin. Results for the NHIRD were consistent with the findings for the CPRD (adjusted hazard ratio 1.34, 95% confidence interval 1.17 to 1.54 for dutasteride, and 1.49, 1.38 to 1.61 for finasteride compared with tamsulosin). Propensity score matched analyses showed similar results

From the results it was concluded that the risk of developing new onset type 2 diabetes appears to be higher in men with benign prostatic hyperplasia exposed to 5α-reductase inhibitors than in men receiving tamsulosin, but did not differ between men receiving dutasteride and those receiving finasteride. Additional monitoring might be required for men starting these drugs, particularly in those with other risk factors for type 2 diabetes

Men using steroid 5α-reductase inhibitors for BPH appear to be at a modest increased risk of developing type 2 diabetes. Caveats exist about biases and confounders within population cohort studies. However, the authors state that in the light of the findings, the decision to prescribe 5α-reductase inhibitors for men with metabolic disease must be considered carefully in the context of other risk factors for type 2 diabetes. In addition, monitoring of fasting glucose might be advisable

Dr Li Wei, Associate Professor from UCL School of Pharmacy and the first author of the study, said: “By studying real word data from different ethnic populations across the UK and Taiwan, we found that men being treated with dutasteride or finasteride for benign prostatic hyperplasia (BPH) have a roughly 30 per cent increased risk of developing diabetes. This demonstrates the importance of how routinely collected healthcare data can be used to identify significant clinical links. It is important that all patients are made aware of the risks and benefits of their medications. In this instance, men should be alerted to the increased risk of diabetes if they are taking these particular medicines for BPH and should speak to their doctor if they are concerned.”

Practice Pearls

  • Men over 50 have a 50 percent chance of having BPH, while men over 80 have a 90 percent chance of having the condition.
  • It is important that men who are diagnosed with BPH and have any risk for type 2 diabetes need to be informed of the risks involved when taking these drugs for BPH.
  • The results of the study need to be explained to men being treated for BPH with dutasteride or finasteride.

The findings have been published in the British Medical Journal.