Differences in admitting hospital characteristics for black and white Medicare beneficiaries with acute myocardial infarction

Abstract

Background: Racial disparities in acute myocardial infarction treatment may be due to differences in admitting hospitals. Little is known about factors associated with hospital selection for black and white acute myocardial infarction patients.

Methods and results: We identified black and white Medicare beneficiaries with acute myocardial infarction in 63 hospital referral regions with at least 50 black admissions during 2005 (n=65,633). We calculated distance from patient home to hospital referral region hospitals using ZIP code centroids. We assessed hospital quality using a composite score made up of hospital risk-adjusted 30-day mortality and acute myocardial infarction performance measures. Hospitals with a score in the top 20% were categorized as high quality, and those in the lowest 20% as low quality. We used conditional multinomial logit models to examine differences in hospital selection for blacks and whites. On average, blacks lived closer to revascularization hospitals (mean, 3.8 versus 6.8 miles; P<0.001) and to high-quality hospitals (mean, 5.6 versus 9.7 miles; P<0.001). After distance was accounted for, blacks were relatively less likely (P<0.001) to be admitted to revascularization hospitals (risk ratio [RR], 0.87; 95% confidence interval [CI], 0.80 to 0.95) and to high-quality hospitals (RR, 0.88; 95% CI, 0.801 to 0.95) but more likely (P<0.001) to be admitted to low-quality hospitals (RR, 1.17; 95% CI, 1.05 to 1.29). In analyses matched by home ZIP code, differences in admissions to revascularization (RR, 0.92; 95% CI, 0.80 to 1.05), high-quality (RR, 0.94; 95% CI, 0.81 to 1.07), and low-quality (RR, 1.15; 95% CI, 0.94 to 1.35) hospitals were not significant.

Conclusions: Differences in admissions to revascularization and high-quality hospitals may contribute to disparities in acute myocardial infarction care. These differences may be due in part to residential ZIP code characteristics.