Question Is the incidence or outcome of out-of-hospital cardiac arrest (OHCA) changing over time overall or among important demographic or clinical groups?
Findings In this cohort study including 25 118 individuals, temporal incidence patterns depended on rhythm and demographic characteristics, with some groups experiencing decrease, some increase, and others no change. In contrast, OHCA outcomes improved over time overall and among shockable and nonshockable subsets.
Meaning The results highlight the dynamic nature of OHCA incidence and resuscitation that provide a foundational context to consider strategies of OHCA prevention and treatment.
Abstract
Importance Incidence and outcome of out-of-hospital cardiac arrest (OHCA) have implications for public health and community strategies to reduce risk and improve resuscitation.
Objective To examine temporal patterns in OHCA incidence and outcome.
Design, Setting, and Participants This was a retrospective cohort investigation conducted in King County, Washington, between 2001 and 2020. Adults with OHCA treated by emergency medical services (EMS) were included in the analysis. Study data were analyzed from May 2024 to April 2025.
Exposures Incidence and clinical outcome of OHCA.
Main Outcomes and Measures Annual incidence was calculated per 100 000 person-years and stratified by sex, age group (<65 years and ≥65 years), and initial rhythm (shockable, nonshockable) with change estimated as average annualized change (AAC) percentage. Resuscitation was assessed according to 5-year groups. Temporal trends were evaluated using Poisson regression for incidence and survival to hospital discharge.
Results There were 25 118 individuals (median [IQR] age, 65 [53-78] years; 15 994 male [63.7%]) with OHCA treated by EMS during 30 884 504 person-years; survival was 17.7%. Overall incidence was 81.3 per 100 000 person-years, 20.9 for shockable and 59.8 for nonshockable OHCA. There was no evidence of linear temporal change in overall incidence: 88.7 in 2001, 82.1 in 2020 (AAC, −0.5%; 95% CI, −0.9% to 0%). However, temporal patterns depended on rhythm and demographic characteristics. For example, shockable rhythm incidence declined (28.6 in 2001 and 17.9 in 2020; AAC, −2.3%; 95% CI, −2.9% to −1.5%), but change was null among nonshockable arrest (59.8 in 2001 and 63.7 in 2020; AAC, 0.3%; 95% CI, −0.1% to 0.8%). Overall survival to hospital discharge improved over time: 14.7% (859 of 5847 individuals; 2001-2005), 17.4% (1024 of 5885 individuals; 2006-2010), 19.3% (1232 of 6376 individuals; 2011-2015), and 18.9% (1322 of 7010; 2016-2020; P < .001 test for trend). Survival increased from 35% (591 of 1689 individuals) during the 2001 to 2005 period to 47.5% (768 of 1617 individuals) during the 2016 to 2020 period among shockable OHCA and from 6.4% (265 of 4135 individuals) during the 2001 to 2005 period to 10.1% (536 of 5323 individuals) during the 2016 to 2020 period among nonshockable OHCA (P < .001 tests for trend). Temporal improvement was observed in prehospital resuscitation (survival to hospital admission) and in-hospital survival (discharge among those admitted to hospital; P < .001 tests for trend). Outcome improvements corresponded to temporal increase in bystander cardiopulmonary resuscitation (55.5% in 2001-2005 to 73.9% in 2016-2020) and early automated external defibrillator application by non-EMS personnel (2.2% in 2001-2005 to 10.9% in 2016-2020; P < .001 tests for trend).
Conclusions and Relevance Results suggest that the overall OHCA incidence did not change over time, although there were differential temporal patterns among clinical subgroups. Survival improved over time overall and according to presenting rhythm, corresponding to favorable trends in community responder, prehospital, and hospital care.
https://jamanetwork.com/journals/jamacardiology/fullarticle/2835966
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