Abstract P25: Identifying Socioeconomic Gradients and Racial/Ethnic Disparities in Outcomes From Ischemic Stroke Hospitalizations

Abstract

OBJECTIVE Even though there are over half a million hospitalizations for acute stroke nationally each year, little attention has been paid to examining racial and ethnic disparities in outcomes, especially inpatient mortality and paralysis. The limited evidence available presents a somewhat confusing picture that is confounded by systematic differences in socioeconomic status (SES) across racial and ethnic populations. STUDY DESIGN We stratified all inpatient admissions for ischemic stroke in all civilian Texas hospitals in 2007 (N=21,203) by sex, age (44-64, 65-74, 75-84 and 85+), race/ethnicity (white, black, Hispanic and other) and zip-code median income (low income = poorest quartile zip codes). Inpatient mortality and paralysis were the outcomes of interest. Secondary diagnosis codes (ICD-9) were used to identify patient risk factors (including atrial fibrillation, hypertension, heart failure and diabetes). Pooled multilevel logistic regression models were estimated to measure mean differences in outcomes across SES and racial/ethnic cohorts. FINDINGS The overall outcome rates -- inpatient mortality=4.9%, paralysis=28.4% -- mask considerable systematic variation. Differences by race/ethnicity are relatively small and not statistically significant: 3.5% (whites), 2.9% (blacks) and 3.8% (Hispanics). However, lower income is associated with a substantially large increase in this risk. Same-race/ethnicity counterparts from lower income zip codes had 47% (whites), 67% (blacks) and 22% (Hispanic) higher inpatient mortality rate (p-value<0.05). Differences in risk adjusted rates of paralysis by race/ethnicity were also not statistically significant - 26% (whites), 29% (blacks) and 30% (Hispanics). But counterparts from lower income zip codes had 20% (whites), 7% (blacks) and 23% (Hispanic) higher rates of paralysis (p-values<0.05). CONCLUSION Among whites, blacks and Hispanics, those residing in poorer zip codes experienced substantially worse rates of inpatient mortality and paralysis. IMPLICATIONS Further study needs to explore the potential pathways connecting lower SES with poorer healthcare outcomes, including, greater patient severity, delayed treatment and access to quality care.