Risk of cardiovascular events in men on abiraterone or enzalutamide combined with GnRH agonists: nation-wide, population-based cohort study in Sweden

Background: Men with prostate cancer (PCa) on gonadotropin-releasing hormone agonists (GnRH) have an increased risk of cardiovascular disease (CVD) compared to men with PCa not on GnRH as well as compared with PCa-free men. Whether the addition of androgen receptor targeted (ART) drugs to GnRH further increases CVD risk, remains to be fully elucidated. Material and methods: We investigated risk of CVD for men with castration resistant PCa (CRPC) on GnRH plus ART; abiraterone or enzalutamide vs 5,127 and 12,079 respective matched comparator men on GnRH in Prostate Cancer data Base Sweden (PCBaSeTraject) 4.1 between 1 June 2015 and 31 December 2018. PCBaSeTraject links National Prostate Cancer Register of Sweden to other healthcare registries and demographic databases. We conducted multivariable Cox proportional hazard models adjusting for PCa risk category, Charlson comorbidity index (CCI), insulin or statin use, civil status, level of education, history of CVD events and number of CVD drugs, with any incident or fatal CVD as the outcome. Results and conclusion: 1,310 men were treated with abiraterone and 3,579 with enzalutamide. In multivariable analysis, CVD risk was increased in men on abiraterone (hazard ratio (HR): 1.19; 95% confidence interval (CI): 1.03–1.38) and in men on enzalutamide (HR: 1.10; 95% CI: 1.01–1.20). Men with a recent CVD (<12 months) including both men on ART as well as comparators had a much higher probability of a new CVD vs men with no prior CVD. CVD risk was mildly increased in men with PCa on GnRH plus abiraterone or enzalutamide vs comparator men on GnRH. Residual confounding and detection bias may at least partly explain this association