Association Between Major Adverse Cardiac Events and Hormone Therapy Usage in Prostate Cancer Patients of a Diverse Cohort

ImportanceHormone therapy (HT) has led to improved overall survival for prostate cancer patients, but may also increase cardiovascular risk. ObjectiveTo compare time-to-event for major adverse cardiovascular events (MACE) between those with and without HT use in prostate cancer patients. Design, Setting, and ParticipantsThis retrospective cohort study examined 5,156 participants from the All of Us Research Program who were diagnosed with prostate cancer and either treated or not treated with HT (defined as exposure to a GnRH agonist, GnRH antagonist, and/or anti-androgens). Time to MACE was defined using longitudinal electronic health record data. We evaluated whether HT use affected the risk of MACE using Cox regression adjusted for established cardiovascular risk factors. ExposuresHT treatment (HT-treated study group), non-HT treatment (control group without HT but with surgery, radiation treatment, and/or non-HT medical therapy), or no treatment (active surveillance control group). Main Outcomes and MeasuresTime-to-event for MACE, which is defined as the interval between the start of treatment (or first prostate cancer diagnosis for the no treatment group) and the date of MACE. Participants who did not develop a MACE were right censored at their last healthcare provider visit. ResultsThe final cohort included 5,156 participants; 851 in the HT treatment group, 624 in the non-HT treatment group, and 3,681 in the no treatment group. In participants with pre-treatment dyslipidemia, HT was found to be associated increased risk of MACE (HR, 1.52; 95% CI, 1.19-1.95; P <.001), while in those without pre-existing dyslipidemia, no association were found (HR, 0.96; 95% CI, 0.71-1.30; P = .81). Similar patterns were found across race and ethnicity groups. The combined androgen blockade was statistically significantly associated with MACE in participants with pre-existing dyslipidemia (HR, 1.58; 95% CI, 1.13-2.19; P= .006) and no association in participants without pre-existing dyslipidemia (HR, 0.96; 95% CI, 0.71-1.30; P= .81). We also observed that HT was associated with prolongation of the QTc interval (P= .02). Conclusions and RelevanceHT treatment was associated with an increased risk for MACE participants with pre-existing dyslipidemia. These results suggest that increased risk stratification can help improve CV outcomes when deciding treatment regimens.