Factors Associated With Racial Differences in Myocardial Infarction Outcomes

Abstract

Little information is available about factors associated with racial differences across a broad spectrum of post-myocardial infarction outcomes, including patients' symptoms and quality of life. To determine racial differences in mortality, rehospitalization, angina, and quality of life after myocardial infarction and identify the factors associated with these differences. Prospective cohort study. 10 hospitals in the United States. 1849 patients who had myocardial infarction, 28% of whom were black. Demographic, economic, clinical, psychosocial, and treatment characteristics and outcomes were prospectively collected. Outcomes included time to 2-year all-cause mortality, 1-year rehospitalization, and Seattle Angina Questionnaire-assessed angina and quality of life. Black patients had higher unadjusted mortality (19.9% vs. 9.3%; P < 0.001) and rehospitalization rates (45.4% vs. 40.4%; P = 0.130), more angina (28.0% vs. 17.8%; P < 0.001), and worse mean quality of life (80.6 [SD, 22.5] vs. 85.9 [SD, 17.2]; P < 0.001). After adjustment for patient characteristics, black patients trended toward greater mortality (hazard ratio, 1.29 [95% CI, 0.92 to 1.81]; P = 0.142), fewer rehospitalizations (hazard ratio, 0.82 [CI, 0.66 to 1.02]; P = 0.071), and higher likelihood of angina at 1 year (odds ratio, 1.41 [CI, 1.03 to 1.94]; P = 0.032) but similar quality of life (mean difference, -0.6 [CI, -3.4 to 2.2]). Adjustment for site of care further attenuated mortality differences (hazard ratio, 1.04 [CI, 0.71 to 1.52]; P = 0.84). Adjustment for treatments had minimal effect on any association. Residual confounding and missing data may have introduced bias. Although black patients with myocardial infarction have worse outcomes than white patients, these differences did not persist after adjustment for patient factors and site of care. Further adjustment for treatments received minimally influenced observed differences. Strategies that focus on improving baseline cardiac risk and hospital factors may do more than treatment-focused strategies to attenuate racial differences in myocardial infarction outcomes. The National Heart, Lung, and Blood Institute Specialized Center of Clinically Oriented Research in Cardiac Dysfunction and Disease, CV Therapeutics, and Cardiovascular Outcomes.