Abstract Body (Do not enter title and authors here): Background: Despite profound disparities in stroke mortality, there is limited research on geographic variation across and within US racial and ethnic populations.

Research Question/Hypothesis: Do geographic trends in stroke mortality vary across and within racial and ethnic populations living in the US? We hypothesized that changes in county-level stroke mortality would vary across and within racial and ethnic groups.

Methods: We applied validated small-area estimation methods to US National Vital Statistics System death certificates to estimate stroke mortality rates by county (N=3110) and race and ethnicity (American Indian or Alaska Native [AIAN], Asian, Black, Hispanic or Latino [Latino], and White) from 2000-19. Mortality estimates were corrected for race and ethnicity misclassification on death certificates and age-standardized to the 2010 Census.

Results: In 2019, age-standardized county-level stroke mortality rates per 100,000 ranged from 10.9 to 170.6 among AIAN, 11.8 to 96.9 among Asian, 17.4 to 179.7 among Black, 6.5 to 114.3 among Latino, and 14.5 to 139.7 among White populations. Despite stroke mortality declining nationally among all racial and ethnic populations, there were counties where mortality increased (AIAN: 15/474; Asian: 46/667; Black: 11/1488; Latino: 154/1478; White: 46/3051), Fig. Among these counties, median absolute increases were 3.5 (IQR 1.9-5.3; max: 26.8) among AIAN, 4.1 (1.1-5.4; max: 12.2) among Asian, 7.1 (1.0-10.2; max: 52.5) among Black, 2.4 (1.3-4.6; max: 18.3) among Latino, and 5.6 (1.9-12.3; max: 47.5) among White populations. Increased stroke mortality largely occurred in the Carolinas, Florida, and Georgia (72.4% of counties with increases) for all racial and ethnic groups except AIAN, which were mostly in Oklahoma (n=9). Geographic and temporal trends also varied across stroke type.

Conclusions: Stroke mortality increased in over 200 counties nationally, with differential effects by race and ethnicity. Most increases occurred in the lower South Atlantic states. These findings underscore the importance of understanding drivers of stroke mortality disparities, as well as creating prevention and treatment strategies that target populations and places at high risk.