Correlations Between County-Level Social Determinants of Health and Traumatic Brain Injury-Related Mortality in the United States.

Nationally representative associations of social determinants of health (SDoH) and health care access metrics with TBI-related mortality are not well described and may differ by age. Using the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiological Research platform and other publicly available datasets, we investigated correlations between county-level measures of SDoH (multidimensional deprivation index, social deprivation index, rural-urban continuum codes) and health care access (median distance to nearest emergency department, trauma center, intensive care unit [ICU], number of hospitals and number of hospitals with ICU capability per 1,000 population) with county-level TBI-related mortality overall and stratified by age in the United States from 1999 through 2020. Data from 2,970 counties (95.4% of eligible U.S. counties) were included. We observed a modest correlation of higher county-level TBI-related mortality with greater rurality (ρ = 0.54, 95% CI = 0.52-0.57, R ² = 0.30). Higher county-level TBI-related mortality was also modestly correlated with farther county-level median distance to nearest hospital with ICU capability (ρ = 0.43, 95% CI = 0.39-0.46, R ² = 0.18). Correlations with SDoH and health care access measures were stronger for county-level TBI-related mortality among younger (aged <50 years) compared to among older (aged ≥75 years) individuals. In conclusion, rurality and access to hospitals with ICU level care are correlated with county-level TBI-related mortality, with rurality accounting for 30% of the observed variance in county-level TBI-related mortality. Rural communities with limited access to ICUs should be targeted for prevention efforts of TBI-related deaths among younger individuals, while additional work is needed to determine factors related to variation in TBI-related mortality among older individuals.