Supplementary Material for: Race/Ethnic Differences in In-Hospital Mortality after Acute Ischemic Stroke

Introduction: Stroke mortality has declined, with differential changes by race; stroke is now the 5th leading cause of death overall, but 2nd leading cause of death in Black individuals. Little is known about recent race/ethnic and sex trends in in-hospital mortality after acute ischemic stroke (AIS) and whether system-level factors contribute to possible differences. Methods: Using the National Inpatient Sample, adults (≥18 years) with a primary diagnosis of AIS from 2006 to 2017 (n=643,912) were identified. We assessed in-hospital mortality by race/ethnicity (White, Black, Hispanic, Asian/Pacific Islander [API], other), sex, and age. Hospitals were categorized by proportion of White patients served: “75% White hospitals”, “50-75% White hospitals”, and “65 years (age x ethnicity interaction p < 0.0001). Compared to White men, Black, Hispanic, and API men, and Black women had lower aOR of mortality. The differences in mortality between White and all the other race/ethnic groups combined were most pronounced in 75% White hospitals (aOR 0.80, 0.74-0.87) compared to 50-75% White hospitals (aOR 0.85, 0.79-0.91) and <50% White hospitals (aOR 0.88, 0.81-0.95; interaction effect: p=0.005). Conclusion: AIS mortality decreased dramatically in recent years in all race/ethnic subgroups. Overall, while individuals of other race/ethnic subgroups had lower mortality odds compared to White individuals, this effect was significantly lower in hospitals serving predominantly White patients compared to those serving minority populations. White patients had higher , mortality than the other race/ethnic groups, a difference that was most striking in hospitals predominantly serving White patients. Further study is needed to understand these differences and to what extent sociocultural, biological, and system-level factors play a role.