ASPO Abstracts
Post-diagnostic metformin and statin use and mortality among Black and White men diagnosed with prostate cancer at the Veteran’s Health Administration
Category: Survivorship & Health Outcomes/Comparative Effectiveness Research
Conference Year: 2019
Abstract Body:
BACKGROUND: Metformin and statins have previously been associated with improved prostate cancer (PCa) outcomes. However, the evidence comes overwhelmingly from studies in White men. Here, we examine the association of post-diagnostic metformin and stain use and mortality in an ethnically diverse cohort. METHODS: Our cohort consisted of 39,858 Black and 105,203 White men diagnosed with PCa between 1997-2009 at the Veterans Health Administration (VHA). Metformin and statin use were defined as any metformin or statin prescription after PCa diagnosis. Death status was determined using VA vital status data, and all alive men were censored on October 1, 2014. Cox proportional hazard models, adjusted for age and PCa grade, were used to assess the association between metformin and statin use with (1) all-cause mortality and (1) PCa-specific mortality. Metformin and statin use were analyzed in separate models stratified by race. RESULTS: Metformin use (24.3% of Black men; 20.7% of White men) and statin use (65.1% of Black men; 69.4% of White men) were prevalent in our cohort. The mean overall survival time was 6.1 years and 6.4 years in Black and White men, respectively. In the cohort as a whole, both metformin and statin use were associated with a reduced risk of all-cause [HR metformin (0.81, 95% CI: 0.79, 0.82); HR statins (0.61, 95% CI: 0.60, 0.62)] and PCa-specific [HR metformin (0.68, 95% CI: 0.64, 0.73); HR statins (0.42, 95% CI: 0.40, 0.44)] mortality. In stratified analyses, metformin use was associated with a reduced risk of all-cause mortality in Black (HR: 0.68, 95% CI: 0.64, 0.71) and White men (HR: 0.86, 95% CI: 0.83, 0.88). Similar reductions in risk were observed for metformin use and PCa-specific mortality [Black men (HR: 0.60, 95% CI: 0.54, 0.68); White men (HR: 0.72, 95% CI: 0.67, 0.77)]. Statin use was also associated with a reduced risk of all-cause mortality in Black (HR: 0.55, 95% CI: 0.54, 0.58) and White men (HR: 0.63, 95% CI: 0.62, 0.64). Greater risk reductions were seen for statin use and PCa-specific mortality [Black men (HR: 0.37, 95% CI: 0.34, 0.41); White men (HR: 0.44, 95% CI: 0.42, 0.47)]. CONCLUSION: Post-diagnostic metformin and statin use may improve survival in both Black and White men with PCa cancer.
Keywords: prostate cancersurvivalmetformin statinsBlack men