Patient Diversity and Population Health-Related Cardiovascular Outcomes Associated with Warfarin Use in Atrial Fibrillation: An Analysis Using Administrative Claims Data

Introduction: Anticoagulants are effective for stroke prevention in atrial fibrillation (AF). Data on population health-related cardiovascular outcomes by race/ethnicity and gender are not well described. The aim was to assess the impact of patient diversity on associated cardiovascular outcomes related to warfarin anticoagulation in Medicare beneficiaries with AF. Methods: Medicare administrative claims data for years 2000–2010 were used to calculate AF prevalence and rates of new AF cases. Three 20% sample cohorts of new AF beneficiaries for years 2000, 2005, and 2007 were extracted and analyzed in a longitudinal study design. The impact of warfarin on associated cardiovascular outcomes was measured with respect to race/ethnicity and gender. Measured outcomes included the risk of stroke, mortality and hospitalization after adjusting for age, gender, race/ethnicity, CHADS2 score and warfarin. Results: AF prevalence and warfarin use increased while stroke and mortality rates declined across race/ethnicity and gender from 2000 to 2010. Analyses comparing Whites to non-Whites highlighted several disparities: (1) Blacks were 40% (p < 0.0001) more likely to have a stroke even after adjustment for warfarin; (2) in 2007, Hispanics had a 35% (p < 0.01) higher prevalence of stroke and warfarin did not reduce the risk; and (3) Asians had better outcomes. Warfarin reduced stroke less well in women who had a lower risk of death and hospitalization. Despite a > 70% (p < 0.0001) reduction in mortality for warfarin users, Blacks had a 25% (p < 0.0001) higher mortality risk than Whites. Conclusions: Differences in population health metrics across race/ethnicity and gender exist in AF. Across all metrics, Blacks had comparatively worse outcomes. Patient diversity should be a focus for future investigations in AF to improve outcomes in the whole population. Funding: National Minority Quality Forum.