Abstract T MP95: Ethnic Differences in Initial Stroke Severity Vary by Age: The Brain Attack Surveillance in Corpus Christi (BASIC) Project

Abstract

Background: Ethnic differences in stroke severity may vary by age or be explained by differences in risk factors (e.g. atrial fibrillation (Afib), diabetes). Our goal was to investigate ethnic differences in initial stroke severity. Methods: Ischemic stroke cases were identified from the population-based BASIC project. NIHSS was determined from the medical record or abstracted from the chart. Ethnicity was ascertained from the medical records and reported as Mexican American (MA) or non-Hispanic white (NHW). Quantile regression was used to model the distribution of NIHSS by age group (45-59, 60-74, 75+) to test whether ethnic differences exist over different quantiles of NIHSS (5% increments). Crude models were run to examine the interaction between age group and ethnicity; models were then adjusted for hypertension, Afib, coronary artery disease, and diabetes. Results were adjusted for multiple comparisons across 19 quantiles (5 to 95%). Results: There were 4,366 ischemic strokes, with median age 72 years (IQR: 61-81), 55% MA and median NIHSS of 4 (IQR: 2-8). In the crude model, in younger (45-59) and older (75+) age groups, MAs had one point higher NIHSS than NHWs at the median and for some lower quantiles (all p<0.001), but no severity difference was seen in the 60-74 group. At the 95% quantile of NIHSS in the younger age group (Figure), MAs had significantly less severe strokes than NHWs by 6 points (p<0.001). However, in the older age group, there was a reversal of this pattern, with MAs’ strokes being more severe than NHWs by about 1 point. After full adjustment, similar trends could be seen at the lower quantiles, but the pattern of older MAs having more severe strokes at the higher quantiles became more apparent at the 85% and 95% quantiles, suggesting that this severity difference was not due to differences in risk factors. Conclusion: Ethnic differences in initial stroke severity varied by age. Age should be considered when looking at race/ethnic differences in severity.