Cardiac Arrest Survival at Emergency Medical Service Agencies in Catchment Areas with Primarily Black and Hispanic Populations

Importance: Black and Hispanic patients are less likely to survive an out-of-hospital cardiac arrest (OHCA) than White patients. Given the central importance of emergency medical service (EMS) agencies in prehospital care, a better understanding of OHCA survival at EMS agencies that work in Black and Hispanic communities and White communities is needed to address OHCA disparities. Objective: To examine whether EMS agencies serving catchment areas with primarily Black and Hispanic populations (Black and Hispanic catchment areas) have different rates of OHCA survival than agencies serving catchment areas with primarily White populations (White catchment areas). Design, Setting, and Participants: A cohort study including adults with nontraumatic OHCA from January 1, 2015, to December 31, 2019, in the Cardiac Arrest Registry to Enhance Survival was conducted. Data analysis was conducted from August 17, 2022, to July 7, 2023. Exposure: Emergency medical service agencies, categorized as working in catchment areas where the combination of Black and Hispanic residents made up more than 50% of the population or where White residents made up more than 50% of the population. Main Outcomes and Measures: The unit of analysis was the EMS agency. The primary outcome was agency-level risk-standardized survival rates (RSSRs) to hospital admission for OHCA at each EMS agency, which were calculated using hierarchical logistic regression and compared between agencies serving Black and Hispanic and White catchment areas. Whether differences in OHCA survival were explained by EMS and first responder measures was evaluated with additional adjustment for these factors. Results: Among 764 EMS agencies representing 258342 OHCAs, 82 EMS agencies (10.7%) had a Black and Hispanic catchment area. Overall median age of the patients was 63.0 (IQR, 52.0-75.0) years, 36.1% were women, and 63.9% were men. Overall, the mean (SD) RSSR was 27.5% (3.6%), with lower survival at EMS agencies with Black and Hispanic catchment areas (25.8% [3.6%]) compared with agencies with White catchment areas (27.7% [3.5%]; P <.001). Among the 82 EMS agencies with Black and Hispanic catchment areas, a disproportionately higher number (32 [39.0%]) was in the lowest survival quartile, whereas a lower number (12 [14.6%]) was in the highest survival quartile. Additional adjustment for EMS response times, EMS termination of resuscitation rates, and first responder rates of initiating cardiopulmonary resuscitation or applying an automated external defibrillator before EMS arrival did not meaningfully attenuate differences in RSSRs between agencies with Black and Hispanic compared with White catchment areas (mean [SD] RSSRs after adjustment, 25.9% [3.3%] vs 27.7% [3.1%]; P <.001). Conclusions and Relevance: Risk-standardized survival rates for OHCA were 1.9% lower at EMS agencies working in Black and Hispanic catchment areas than in White catchment areas. This difference was not explained by EMS response times, rates of EMS termination of resuscitation, or first responder rates of initiating cardiopulmonary resuscitation or applying an automated external defibrillator. These findings suggest there is a need for further assessment of these discrepancies..