Provider Care Segregation and Hospital-Region Racial Disparities in the United States for Acute Ischemic Stroke and Endovascular Therapy Outcomes.

BACKGROUND: Reasons for racial disparities in the use and outcomes of endovascular treatment (ET) are not known. We examined patterns in care segregation for acute ischemic stroke (AIS) in the United States, and outcomes of segregation of care after ET.

METHODS AND RESULTS: We used deidentified Medicare data sets to identify AIS admissions between January 1, 2016 and December 31, 2019, using validated International Classification of Diseases, Tenth Revision ( ICD-10 ) codes. For AIS, we calculated (1) the proportion of White patients at the hospital, (2) the proportional difference in the proportion of White patients between hospital patients and the county, and (3) provider care segregation by the dissimilarity index for ET cases. Using unadjusted and adjusted multilevel logistic models, we examined associations between measures of segregation and outcomes of discharge home, inpatient mortality, and 30-day mortality. The mean proportional difference in the proportion of White patients comparing hospitalized patients with AIS to the county race distribution was 0.015 (SD, 0.219) at the hospital level. For ET, the mean proportional difference in the proportion of White patients comparing patients receiving ET to the county race distribution was much higher, at 0.146 (SD, 0.374). The dissimilarity index for ET providers was high, with a mean of 0.48 (SD, 0.29) across all hospitals. Black patients with AIS (compared with White patients) had reduced odds of discharge home, inpatient mortality, and 30-day mortality.

CONCLUSIONS: In this national study with contemporary data in the endovascular era of AIS treatment, we found substantial evidence for segregation of care in the United States, not for only AIS in general but also especially for ET.