Abstract MP29: Effects of System-Level Factors on Race/Ethnic Differences in In-Hospital Mortality After Acute Ischemic Stroke

Abstract

Introduction: Stroke mortality has declined, with differential changes by race; stroke is now the 5 th leading cause of death overall, but 2 nd leading cause of death in blacks. Little is known about recent race/ethnic 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 yrs) with a primary diagnosis of AIS from 2006 to 2017 (n=763,808) 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 minority patients served: <25% minority (white hospitals); 25-50% (mixed hospitals), and >50% (minority hospitals). Using survey adjusted logistic regression, the association between race/ethnicity and odds of mortality was assessed, adjusting for key sociodemographic, clinical, and hospital characteristics (e.g. age, comorbidities, stroke severity, DNR status, and palliative care). Results: Overall, mortality decreased from 5.0% in 2006 to 2.9% in 2017, p<0.001. Comparing 2006-2011 to 2012-2017, there was a 66% reduction in mortality after adjustment for covariates, most prominent in whites (68%) and smallest in blacks (58%). Compared to whites, blacks and Hispanics had lower adjusted odds of mortality (AOR 0.82, 95% CI 0.78-0.86 and AOR 0.92, CI 0.86-0.98), primarily driven by those >65 yrs (age x ethnicity interaction p = 0.003). Compared to white men, black, Hispanic, and API men and black women had lower odds of mortality. Adjusted mortality was lower in minorities vs. whites and most pronounced in white hospitals (white: AOR 0.78, 0.73-0.85; mixed: 0.85, 0.80-0.91; minority: 0.89, 0.82-0.95; interaction effect: p=0.018). These differences were present for both minority men and women in white and mixed hospitals, but not women in minority hospitals. Discussion: AIS mortality decreased dramatically in recent years. Overall, black and Hispanic AIS patients have lower mortality than whites, a difference that is most striking in white hospitals. Further study is needed to understand these differences and to what extent biological, sociocultural, and system-level factors play a role.