Correlation Between EMS Agency Rates of Survival to Hospital Admission and Hospital Survival Outcomes for Cardiac Arrest

BACKGROUND: Survival to hospital admission for out-of-hospital cardiac arrest is an important resuscitation outcome to gauge emergency medical service (EMS) agency performance. However, its correlation with EMS rates of survival to hospital discharge and favorable neurological survival is unclear. METHODS: Using the Cardiac Arrest Registry to Enhance Survival (CARES), we identified adults with nontraumatic out-of-hospital cardiac arrests during 2 periods: 2015 through 2019 (before the COVID-19 pandemic) and 2022 through 2024 (after the peak pandemic years). Multivariable hierarchical logistic regression was used to derive EMS agency-level risk-standardized survival rates for hospital admission, hospital discharge, and favorable neurological survival during each period. We then assessed the correlation between EMS agency rates of survival to admission versus discharge and favorable neurological survival using weighted linear regression, and whether the correlations differed by neighborhood income (above versus below median household income) and race and ethnicity (categorized as predominantly White [>80% of residents], majority Black or Hispanic [>50% of residents], or integrated). RESULTS: A total of 544 296 events from 1838 EMS agencies met inclusion criteria (252 137 pre-COVID; 292 159 post-COVID). During the period of 2015 to 2019, EMS rates of survival to admission were strongly correlated with survival to discharge (weighted r =0.68 [95% CI, 0.64–0.72]) and favorable neurological survival (weighted r =0.54 [95% CI, 0.43–0.59]). These correlations were similar during the period of 2022 through 2024 (weighted r =0.63 [95% CI, 0.59–0.66] and weighted r =0.48 [95% CI, 0.44–0.53], respectively). Neighborhood racial and ethnic composition modified the correlation between EMS rates of survival to admission and survival outcomes at discharge in both periods (all interactions <0.05), but the correlations remained strong in each neighborhood group. Similar findings were found for the interactions by neighborhood income strata. CONCLUSIONS: EMS agency rates of survival to hospital admission are strongly correlated with their rates of survival to hospital discharge and favorable neurological survival. These findings support the use of survival to hospital admission as a performance metric for EMS systems.