Metformin significantly reduces incident prostate cancer risk in Taiwanese men with type 2 diabetes mellitus
Journal
European Journal of Cancer
Journal Volume
50
Journal Issue
16
Pages
2831-2837
Date Issued
2014
Author(s)
Abstract
Background Whether metformin therapy affects incident prostate cancer risk in Asian patients with type 2 diabetes mellitus (T2DM) has not been investigated. Methods The National Health Insurance reimbursement database of Taiwanese male patients with new-onset T2DM between 1998 and 2002 and aged ?40 years (n = 395,481) were retrieved to follow up prostate cancer incidence until the end of 2009. Metformin was treated as a time-dependent variable. Of the patients studied, 209,269 were never-users and 186,212 were ever-users. A time-dependent approach was used to calculate prostate cancer incidence and estimate hazard ratios using Cox regression for ever-users, never-users and subgroups of metformin exposure (tertiles of cumulative duration and cumulative dose). Sensitivity analyses were conducted in various subgroups, using time-dependent and non-time-dependent approaches. Results During the follow-up, 2776 metformin ever-users and 9642 never-users developed prostate cancer, representing an incidence of 239.42 and 737.10 per 100,000 person-years, respectively. The hazard ratio (95% confidence intervals) after adjustment for propensity score (PS) for ever- versus never-users was 0.467 (0.446-0.488). The PS-adjusted hazard ratios for the first, second and third tertiles of cumulative duration of metformin therapy were 0.741 (0.698-0.786), 0.474 (0.441-0.508) and 0.231 (0.212-0.253), respectively (P-trend < 0.001); and were 0.742 (0.700-0.786), 0.436 (0.406-0.468) and 0.228 (0.208-0.251) for the respective cumulative dose (P-trend < 0.001). Sensitivity analyses consistently supported a protective effect of metformin on incident prostate cancer. Conclusions Metformin use is associated with a decreased risk of incident prostate cancer in Taiwanese male patients with T2DM. ? 2014 Elsevier Ltd. All rights reserved.
SDGs
Other Subjects
metformin; antidiabetic agent; metformin; adult; Article; cancer incidence; cancer prevention; cancer risk; cohort analysis; dose time effect relation; follow up; human; major clinical study; male; middle aged; non insulin dependent diabetes mellitus; population research; priority journal; prostate cancer; retrospective study; sensitivity analysis; Taiwanese; treatment duration; aged; complication; Diabetes Complications; Diabetes Mellitus, Type 2; incidence; proportional hazards model; Prostatic Neoplasms; risk factor; Taiwan; treatment outcome; Adult; Aged; Diabetes Complications; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Incidence; Male; Metformin; Middle Aged; Proportional Hazards Models; Prostatic Neoplasms; Retrospective Studies; Risk Factors; Taiwan; Treatment Outcome
Publisher
Elsevier Ltd
Type
journal article