Abstract 11097: Racial Differences in Clinical Outcomes in Elderly Patients With Atrial Fibrillation

Abstract

Introduction: Atrial fibrillation (AF) is associated with stroke and death, but the effect of race on these outcomes is not known. Methods: Medicare administrative data from 2010-2011 were used to identify patients with newly diagnosed AF who were categorized based on race as white, black and Hispanic. Racial differences in the primary outcome of death and secondary outcomes of stroke and the composite of stroke and death were assessed using Cox proportional hazard models. Results: Among 517,941 patients with newly diagnosed AF, 452,986 (87%) were whites, 36,425 (7%) were blacks and 28,530 (6%) were Hispanics. The mean age was 79 ± 8 years and 40.5% were males. Over a mean follow-up period of 0.9 years per patient, 68,250 (15.1%) whites, 7665 (20%) blacks and 4814 (16.9%) Hispanics died. Stroke was diagnosed in 6,509 (1.4%) whites, 843 (2.3%) blacks and 507 (1.8%) Hispanics. Compared to whites, blacks had a significantly higher hazard of death (Hazard Ratio [HR] =1.43; 95% CI 1.40-1.47; p<0.001), stroke (HR=1.69; 95% CI 1.57-1.81; p<0.001), and the composite outcome (HR= 1.46; 95% CI 1.43-1.49; p<0.001). After controlling for pre-existing co-morbidities, the higher hazard of death (HR 0.99; 95% CI 0.97-1.01; p=0.41) and the composite outcome (HR=1.02; 95% CI 0.99-1.04; p=0.135) in blacks were eliminated and the relative hazard of stroke (HR=1.44; 95% CI 1.34-1.55; p<0.001) was reduced compared to the whites. Similarly, Hispanics had a higher risk of death (HR= 1.13; 95% CI 1.10-1.17; p<0.001), stroke (HR=1.26; 95% CI, 1.15-1.38; p<0.001) and the composite outcome (HR= 1.15; 95% CI 1.12-1.18; p<0.001), as compared to whites. The relative hazard of death and the composite outcome were noted to be lower in Hispanics, compared to whites, after controlling for pre-existing co- morbidities (HR= 0.93; 95% CI 0.92-0.96; p<0.001 and HR= 0.95; 95% CI 0.92-0.97; p<0.001 respectively). The relative hazard of stroke was also attenuated (HR=1.15; 95% CI 1.05-1.26; p=0.002). Conclusions: In an elderly Medicare population with newly diagnosed AF, the risks of death and stroke are higher in blacks and Hispanics, as compared to whites. This is likely due to increased co-morbidities in blacks and Hispanics.