Antidiabetic drug use and prostate cancer risk in the Finnish Randomized Study of Screening for Prostate Cancer

AbstractObjective: Diabetic men have lowered overall prostate cancer (PCa) risk, while their risk of high-grade disease may be elevated. The antidiabetic drug metformin may reduce the risk. This study evaluated PCa incidence among users of metformin and other antidiabetic drugs in the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC).Methods: The study population (78,615 men) was linked to the national prescription database. Hazard ratios (HRs) and 95% confidence intervals (CIs) for PCa were estimated using Cox regression, with medication use as a time-dependent variable. The effect of diabetes was estimated by comparing antidiabetic drug users to non-users, while drug-specific effects were evaluated within antidiabetic drug users. Analyses were performed in both study arms of FinRSPC.Results: Compared to non-users, men using antidiabetic drugs had lowered overall PCa risk (HR 0.85, 95% CI 0.79–0.92), and this association was not affected by PCa screening. However, the risk of metastatic...