Background: 

Previous studies have documented racial disparities in treatment of acute myocardial infarction (AMI) among Medicare beneficiaries. However, the extent to which unobserved differences between hospitals explains some of these differences is unknown.

Objective: 

The objective of this study was to determine whether the observed racial treatment disparities for AMI narrow when analyses account for differences in where blacks and whites are hospitalized.

Research Design: 

Retrospective observational cohort study using Medicare claims and medical record review.

Subjects: 

This study included 130,709 white and 8286 black Medicare patients treated in 4690 hospitals in 50 US states for confirmed AMI in 1994 and 1995.

Measures: 

Measures in this study were receipt of reperfusion, aspirin, and smoking cessation counseling during hospitalization; prescription of aspirin, angiotensin-converting enzyme inhibitor, and beta-blocker at hospital discharge; receipt of cardiac catheterization, percutaneous coronary intervention (PCI), or bypass surgery (CABG) within 30 days of AMI; and 30-day and 1-year mortality.

Results: 

Within-hospital analyses narrowed or erased black–white disparities for medical treatments received during the acute hospitalization, widened black–white disparities for follow-up surgical treatments, and augmented the survival advantage among blacks. These findings indicate that, on average, blacks went to hospitals that had lower rates of evidence-based medical treatments, higher rates of cardiac procedures, and worse risk-adjusted mortality after AMI.

Conclusions: 

Incorporating the hospital effect altered the findings of racial disparity analyses in AMI and explained more of the disparities than race. A policy of targeted hospital-level interventions may be required for success of national efforts to reduce disparities.