Rapid Access to Emergency Medical Services Within Historically Redlined Areas.

Importance: Inequities in rapid access to emergency medical services (EMS) represent a critical gap in prehospital care and the first system-level milestone for critically injured patients. As delays in EMS response are associated with increased mortality and known disparities within historically redlined areas are prevalent, this study sought to examine disparities in rapid access to EMS across the United States. Objective: To assess the association between historically redlined areas and rapid EMS access (defined as ≤5-minute response time) across the United States. Design, Setting, and Participants: This retrospective, cross-sectional study analyzed the geographic distribution of EMS centers in relation to 2020 US Census block groups and Home Owners' Loan Corporation (HOLC) residential security maps, classified by grades (A-D). Populations of 236 US cities with publicly available redlining data were included. Travel distance radius (5-minute drive times) was centered on population-weighted block group centroids. Redlining grades include A ("most desirable," green), B ("still desirable," blue), C ("declining," yellow), and D ("hazardous," red). Exposure: HOLC grade classification (A-D). Main Outcomes and Measures: The primary outcome was the proportion of the population with rapid EMS access. Secondary outcomes included the socioeconomic and demographic profiles of populations without rapid access. Results: Of the total US population (N = 333 036 755), 41 367 025 (12.42%) lived in cities with redlining data. Among these, 2 208 269 (5.34%) lacked rapid access to 42 472 EMS stations. Grade D areas had a higher proportion of residents without rapid EMS access compared with grade A areas (7.06% vs 4.36%; P < .001). The odds of having no rapid access to EMS in grade D areas were 1.67 (95% CI, 1.66-1.68) times higher than in grade A areas. Compared with grade A, grade D areas had a lower percentage of non-Hispanic White residents (65.21% [95% CI, 59.43%-70.99%] vs 39.36% [95% CI, 36.99%-41.73%]; P < .001), a higher percentage of non-Hispanic Black residents (10.38% [95% CI, 7.14%-13.62%] vs 27.85% [95% CI, 25.4%-30.3%]; P < .001), and greater population density (7500.72 [95% CI, 4341.26-10 660.18] persons/km2 vs 15 277.87 [95% CI, 13 281.7-17 274.04] persons/km2; P < .001). Conclusions and Relevance: In this cross-sectional study, structural disparities in rapid EMS access were associated with historically redlined areas. Strategic resource allocation and system redesign are warranted to address these inequities in prehospital emergency care.