Abstract Body (Do not enter title and authors here): Background: Chemotherapy is associated with increased cardiovascular risk in breast cancer patients, yet the influence of racial and ethnic disparities on atrial fibrillation (Afib) and cardiomyopathy outcomes remains understudied.
Hypothesis: Chemotherapy increases Afib and cardiomyopathy risk in breast cancer patients, with older age, pre-existing cardiac risk, and racial/ethnic differences (particularly among Black and Hispanic patients) contributing to differential risk profiles.
Methods: We analyzed 1,193 female breast cancer patients from the All of Us workbench dataset who received chemotherapy and developed cardiovascular diseases, including Afib (n=723) or cardiomyopathy (n=284). Firth-corrected Cox proportional hazards models (penalizer=0.5) assessed the effects of age, pre-existing cardiac risk, race (White, Black, Asian, Other), ethnicity (Hispanic vs. non-Hispanic), and age group (<65 vs. ≥65 years) on time to Afib or cardiomyopathy.
Results: Age significantly increased Afib (HR=1.01, 95% CI: 1.01-1.02, P<0.005) and cardiomyopathy risk (HR=1.02, 95% CI: 1.01-1.03, p=0.002). Pre-existing cardiac risk showed non-significant trends for Afib (HR=1.09, 95% CI: 0.98-1.21, p=0.098) and cardiomyopathy (HR=1.12, 95% CI: 0.95-1.32, p=0.17). Black patients (n=189) had higher Afib incidence (4.8%) than White patients (n=762, 3.2%), with stronger cardiac risk effects (HR=1.25, 95% CI: 1.02-1.53, p=0.03). Hispanic patients (n=231) had lower Afib incidence (2.9%) than non-Hispanic patients (3.7%). Patients ≥65 years (n=524) had elevated Afib risk (HR=1.15, 95% CI: 1.05-1.26, p=0.003).
Conclusion: Older age and Black race are associated with increased Afib risk post-chemotherapy, while Hispanic patients may have lower risk. These findings highlight the need for targeted cardio-oncology interventions to address disparities.