Association between Geospatial Access to Care and Firearm Injury Mortality in Philadelphia

Importance: The burden of firearm violence in US cities continues to rise. The role of access to trauma center care as a trauma system measure with implications for firearm injury mortality has not been comprehensively evaluated. Objective: To evaluate the association between geospatial access to care and firearm injury mortality in an urban trauma system. Design, Setting, and Participants: Retrospective cohort study of all people 15 years and older shot due to interpersonal violence in Philadelphia, Pennsylvania, between January 1, 2015, and August 9, 2021. Exposures: Geospatial access to care, defined as the predicted ground transport time to the nearest trauma center for each person shot, derived by geospatial network analysis. Main Outcomes and Measures: Risk-adjusted mortality estimated using hierarchical logistic regression. The population attributable fraction was used to estimate the proportion of fatalities attributable to disparities in geospatial access to care. Results: During the study period, 10105 people (910 [9%] female and 9195 [91%] male; median [IQR] age, 26 [21-28] years; 8441 [84%] Black, 1596 [16%] White, and 68 other [<1%], including Asian and unknown, consolidated owing to small numbers) were shot due to interpersonal violence in Philadelphia. Of these, 1999 (20%) died. The median (IQR) predicted transport time was 5.6 (3.8-7.2) minutes. After risk adjustment, each additional minute of predicted ground transport time was associated with an increase in odds of mortality (odds ratio [OR], 1.03 per minute; 95% CI, 1.01-1.05). Calculation of the population attributable fraction using mortality rate ratios for incremental 1-minute increases in predicted ground transport time estimated that 23% of shooting fatalities could be attributed to differences in access to care, equivalent to 455 deaths over the study period. Conclusions and Relevance: These findings indicate that geospatial access to care may be an important trauma system measure, improvements to which may result in reduced deaths from gun violence in US cities..