Metformin does not reduce BPH incidence in men with diabetes: BMJ study
It has been hypothesised that insulin resistance and increased fasting plasma insulin are promoters of both Benign prostatic hyperplasia (BPH) and prostate cancer.
A recent study suggests metformin did not substantially reduce the incidence of BPH in men with diabetes when compared with the sulfonylurea. The study findings are published in the journal BMJ on December 22, 2020.
The prevalence of BPH has increased from 25% in the age group of 40–49 to 80% in 70–79 years age group. Among men with type 2 diabetes, some observational studies have suggested that use of metformin reduces the risk of prostate cancer, compared with the use of other glucose-lowering drugs (GLDs) while others found no clear association. In the late first half of the 2000s, metformin and sulfonylurea were both widely recommended and used as first-line treatment for type 2 diabetes in Denmark. However, the long term risk of BPH in men with T2D who initiated pharmacotherapy with either metformin or sulfonylurea remains unclear. For this purpose, researchers of the Aarhus University and Aarhus University Hospital, Denmark conducted a study to assess whether metformin use affects the risk of benign prostatic hyperplasia (BPH) by comparing the risk of BPH in men with type 2 diabetes who initiated first-line treatment with either metformin or sulfonylurea monotherapy between 2000 or 2006 in Northern Denmark.
It was a northern Denmark population-based cohort study. Researchers compared BPH risk among men with type 2 diabetes who started first-line therapy with either metformin (n=3953) or sulfonylurea (n=5958) monotherapy between 2000 or 2006. They enrolled all men who filled at least two prescriptions for metformin or sulfonylurea respectively, during their first 6 months of GLD treatment and followed them for 6 months after initiation of treatment. The major outcome assessed was the rates of subsequent BPH. It was identified based on community prescriptions for BPH-related treatment or hospital BPH diagnoses, and rates of transurethral resection of the prostate (TURP).
Key findings of the study were:
• Upon median observation for 10 years, researchers found the 10 years cumulative BPH incidence was estimated to be 25.7% in metformin initiators.
• Similarly, for sulfonylurea initiators, the 10-year cumulative incidence was 27.4% (median observation 8 years)
• They also found that the crude Hazards ratio (HR) for BPH and adjusted HR in the intention-to-treat analyses (ITT) were estimated to be 0.83 and 0.97, respectively.
• For TURP, they found the adjusted HR as 0.96 and for the as-treated analysis, adjusted HR for BPH was 0.91.
Overall, findings revealed that no substantial decrease in BPH incidence was conferred by metformin vs sulfonylurea use in men with diabetes.
The authors concluded, "Compared with sulfonylurea, metformin did not substantially reduce the incidence of BPH in men with diabetes".
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