Abstract Sat604: Mean age at Out-of-Hospital Cardiac Arrest: National trends

Background: While a decrease in mean age has been reported in out-of-hospital cardiac arrest (OHCA) cases regionally in Chicago, it is not known if similar trends are observed nationally. Therefore, this analysis was conducted to assess the trends in mean age at a national level. Methods: We analyzed adult (>=18 years) non-traumatic OHCA cases reported to the Cardiac Arrest Registry to Enhance Survival (CARES) from 2018 to 2023. We restricted the sample to only those Emergency Medical Services that reported cases throughout 2018-2023. We excluded pediatric cases, and cases with missing age. The annual data were combined to create two-year cycles. We also conducted a secondary analysis restricted to presumed cardiac etiology (CE). The trends in the mean age were assessed overall, and by sex and race/ethnicity using linear regression models. Results: In the 519,176 cases included in the primary analysis, the overall mean age was 63.5 (SD=17), and the median was 65 years. Mean age decreased from 63.9 years in 2018-19 to 63.2 in 2020-21, and remained at 63.3 in 2022-23. A similar pattern was observed in CE cases, where mean age reduced from 66 years to 65.7 during the study period. Among female OHCA cases, the mean age reduced (from 65.7 to 65.1 years overall, and 67.9 to 67.3 years in CE cases) during the study period. Similarly, in males an overall decrease was observed, but it was not consistent across cycles. A consistent decrease in mean age was noticed in Black cases, overall (from 62.7 to 61.4 years; biennial change -0.65; p=0.03), and in CE cases (from 64 to 63.1 years; biennial change -0.45; p=0.04). Similarly, a consistent decrease was observed in Hispanic cases, overall (from 60.6 to 58.5; biennial change -1; p=0.087), and in CE cases (63 to 61.4 years; p=0.14) but it did not reach statistical significance. The decrease in mean age was paralleled by a consistent decrease in median age in Hispanic cases. Conclusion: A decrease in mean age of OHCA has been observed, especially with consistent decrease noticed among Black and Hispanic cases. While the pandemic may account for some of the sharper decrease seen in most groups from 2018-19 to 2020-21, the decrease in mean age has continued for many groups. Whether these trends are due to earlier onset of cardiac disease or other conditions such as drug overdose deserves further study. Decreasing age at OHCA will lead to higher years of potential life lost, which needs to be examined at a national level.