Abstract Body: Introduction: Our understanding of the epidemiology of out-of-hospital cardiac arrest (OHCA) has increased with the establishment of national registries. However, the use of EMS-treated OHCA as the indicator of incidence and the denominator for outcomes underestimates the burden of disease, limits the ability to benchmark EMS system performance regionally and over time, and does not inform the overall population health impact of OHCA care.

Goals: The goal of this analysis is to create a methodology to quantify the public health impact of OHCA care in the United States.

Methods: Publicly available national and state data from the Cardiac Arrest Registry to Enhance Survival (CARES) and Center for Disease Control and Prevention (CDC) WONDER database for the years 2020 to 2024 were used. CARES data included population covered, total population, incidence of EMS treated OHCA, and survival rate. CDC data included the annual number of all-cause deaths. These data were used to calculate the percent of total deaths that were EMS treated OHCA, and the percent reduction in all-cause mortality attributable to EMS OHCA treatment (Tables 1-3).

Results: Between 2020 and 2024, and estimated 7.9% of all-cause deaths in the United States were EMS-treated OHCAs. EMS-treated OHCA survival rate averaged 9.6% resulting in an 0.8% reduction in all-cause mortality attributable to OHCA treatment or an average of 27,312 annual deaths prevented. State level variability in all-cause deaths treated as OHCA ranged from 5.5% to 10.5%. EMS treated OHCA survival rates ranged from 6.6% to 15.2%. The reduction in all-cause mortality attributable to OHCA treatment ranged from 0.4% to 1.3%. Notably, variability in both survival rate and the percent of all-cause deaths treated as OHCA contributed to the state level variability in all-cause mortality reduction attributable to OHCA care.

At the national level, the reduction in all cause mortality attributable to OHCA care increased from 0.8% in 2020 to 0.9% in 2024. The greatest improvement occurred in Alaska (1.1% to 1.4%) Delaware (1.1% to 1.5%), Hawaii (1.0 to 1.5%) and Utah (0.6% to 1.3%). These improvements were predominantly driven by improved survival rates rather than changes in the percent of all-cause deaths treated as OHCA.

Conclusion: These results provide a novel and informative methodology to benchmark the public health impact of OHCA treatment, compare systems of care, and monitor trends over time.