Dispatch disparities: Neighborhood segregation as a predictor of EMS triage discordance among critically injured trauma patients.
The journal of trauma and acute care surgery · 2026-06-05 · Registry study
Abstract
BACKGROUND: Timely emergency medical services (EMS) response is critical to improving survival after trauma. However, concordance between EMS dispatch level and on-scene patient acuity remains poorly understood. This study evaluated the association between racial and ethnic residential segregation and concordance between EMS response level and on-scene acuity among critically injured trauma patients. METHODS: Using 2018-2022 National EMS Information System data, we analyzed trauma patient entries meeting CDC field triage criteria for transport to a trauma center. Concordance was defined as alignment between dispatch classification of response (emergent vs. nonemergent) and EMS providers' subsequent on-scene clinical assessment of acuity (critical/emergent vs. noncritical/low acuity). Racial and ethnic residential segregation at the ZIP Code level was measured using a multigroup dissimilarity index comparing neighborhood composition to county distribution. χ2 tests and multivariable logistic regression were used to assess the associations between segregation and under-triage, adjusting for region (Northeast, Midwest, South, West). RESULTS: Among 34.7 million critically injured patients over 5 years, 69% had concordant EMS responses, 6% were under-triaged, and 26% over-triaged. Concordance was highest in the Midwest (74%) and lowest in the Northeast (62%). Under-triage was most frequent in the West (10%) and least in the South (4%). Neighborhoods with medium and high segregation had twice the under-triage rates than low-segregation areas (8% and 7% vs. 4%, p<0.001). In adjusted analyses, medium and high segregation were 60% more likely to be associated with increased odds of under-triage (odds ratio: 1.61, 95% confidence: 1.60-1.61). CONCLUSIONS: This is the largest study to date demonstrating that racial and ethnic residential segregation was significantly associated with meaningfully and significantly increased risk of under-triage among critically injured trauma patients. Furthermore, structural inequities in neighborhood segregation may delay access to definitive trauma care. Equity-driven EMS policy reform, standardized dispatch protocols, and targeted training are needed to mitigate disparities in prehospital trauma response. (J Trauma Acute Care Surg 2026;00:000-000. Copyright © 2026 Wolters Kluwer Health, Inc. All rights reserved.). LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.