Metformin for Reducing Racial/Ethnic Difference in Prostate Cancer Incidence for Men with Type 2 Diabetes
Menée à partir de données portant sur 76 733 patients atteints d'un diabète de type 2 (durée moyenne de suivi : 6,4 ans), cette étude évalue, en fonction de l'appartenance ethnique des patients, l'association entre l'utilisation de metformine, seule ou en combinaison avec le finastéride ou une statine, et le risque de cancer de la prostate
Racial/ethnic disparity in prostate cancer (PCa) is under studied in men with diabetes who are at higher risk for aggressive PCa. This study assessed the race/ethnic disparity in PCa incidence for men with type 2 diabetes (T2D), and whether the impact of metformin on PCa incidence varied by race/ethnicity. We conducted a retrospective study in 76,733 male veterans with T2D during 2003-2012. Cox proportional hazard model adjusting for covariates and propensity scores of metformin use and race/ethnic group membership were utilized to compute the hazard ratio (HR) of PCa incidence associated with race/ethnicity, and compare HR associated with metformin use between race/ethnic groups. Mean follow-up was 6.4{plus minus}2.8 years; 7% were Hispanics; 17% were African American (AA); mean age was 67.8{plus minus}9.8 years; 5.2% developed PCa; 38.9% used metformin. Among these diabetic men without metformin use, PCa incidence was higher in Hispanics and AA than in non-Hispanic White (NHW). Use of metformin alone or metformin+statins was associated with a greater PCa incidence reduction in Hispanics compared to NHW, but not between AA and NHW. Use of metformin+finasteride was associated with a greater PCa incidence reduction in Hispanics and AA compared to NHW. Our results suggested that metformin treatment could be a potential strategy to reduce PCa incidence in the minority populations who are at high risk for fatal PCa. It will be important to further examine the pleiotropic effects of metformin in multi-race/ethnic prospective studies to better inform clinical management, and potentially reduce racial/ethnic disparity in PCa incidence among diabetic men.