Patient Race/Ethnicity, Socioeconomic Status, and Acute Myocardial Infarction Mortality: Between-Hospital Versus Within-Hospital Disparities.

BACKGROUND

Prior work often finds racial/ethnic differences in mortality following acute myocardial infarction (AMI), but is subject to selection bias. Similar selection issues arise for differences associated with socioeconomic status (SES).

OBJECTIVES

Re-examine the association between patient race/ethnicity, area-level socioeconomic status (area-SES), and post-AMI mortality using a data source that limits patient selection of hospital or cardiologist, or vice-versa, and which lets us distinguish between-hospital from within-hospital sources of differences.

RESEARCH

DESIGN

We compare mortality disparities with no controls, with controls typical of the prior literature ("typical controls"), and more extensive controls, including hospital, cardiologist, and calendar quarter fixed effects (FEs).

SUBJECTS: The study uses a 100% sample of 681,000 Medicare Fee-for-Service patients aged 68+ hospitalized for incident (first) AMI over 2008-2019.

MEASURES: Post-AMI mortality in-hospital, within 30 days after discharge and over periods up to 3 years post-discharge. We study patients with ST-segment elevation MI (STEMI) and non-ST-segment elevation MI (nSTEMI) separately.

RESULTS

With no or typical controls, Blacks, Hispanics, and Asians have higher in-hospital mortality than Whites; lower SES also predicts higher mortality. However, higher mortality is substantially explained by between-hospital differences in mortality rates. Longer-term mortality is higher for Black patients, consistent with the importance of post-discharge pathways.

CONCLUSIONS

Post-AMI disparities in outcomes can be strongly affected by selection effects, especially the tendency for poor and minority persons to be treated at lower-quality hospitals. Disparities measurement and policy discussions should distinguish access-related hospital sorting from within-hospital processes and pay greater attention to post-discharge pathways.