Cardiac Arrest Survival Up, Incidence Stable Over 20 Years

Survival after out-of-hospital cardiac arrest (OHCA) has improved over the past two decades, even as overall incidence remained stable, according to a large population-based study conducted in a representative US region published in JAMA Cardiology. The gains appear tied to increased bystander cardiopulmonary resuscitation (CPR) and early use of defibrillators.

“Out-of-hospital cardiac arrest is a significant public health challenge, claiming hundreds of thousands of lives in the US and millions of lives worldwide each year,” explained the study authors. “[T]he overall and rhythm-specific incidences of OHCA have implications for public health and community strategies designed to prevent OHCA and improve resuscitation.”

The investigators conducted a retrospective cohort study to evaluate temporal patterns in OHCA incidence and outcomes. They used data for all emergency medical services (EMS)-treated adult patients with OHCA (≥18 years) in King County, Washington—a metropolitan region including urban, suburban, rural, and wilderness areas—from 2001 to 2020.

Key outcomes and measures included annual OHCA incidence (per 100,000 person-years), stratified by sex, age group (<65 vs ≥65 years), and initial rhythm (shockable vs non-shockable); resuscitation outcomes assessed in 5-year intervals; and temporal trends in both incidence and survival to hospital discharge.

During the 20-year period, there were 25 118 adults with OHCA (median age, 65 years; interquartile range, 53-78 years; 63.7% male) during 30 884 504 person-years, translating to an overall incidence of 81.3 per 100 000 person-years, 20.9 for shockable and 59.8 for non-shockable OHCA.

The analysis found no evidence of temporal change in overall incidence of OHCA (88.7 in 2001 and 82.1 in 2020; average annualized change [AAC], -0.5%; 95% confidence interval [CI], -0.9% to 0%) but revealed temporal patterns based on rhythm and demographic characteristics. Notably, shockable rhythm incidence declined (28.6 in 2001 and 17.9 in 2020; AAC, -2.3%; 95% CI, -2.9% to -1.5%), while non-shockable arrest was largely unchanged (59.8 in 2001 and 63.7 in 2020; AAC, 0.3%; 95% CI, -0.1% to 0.8%).

Overall survival to hospital discharge was 17.7%, and this improved with time: 14.7% in 2001-2005, 17.4% in 2006-2010, 19.3% in 2011-2015, and 18.9% in 2016-2020 (P<.001 for trend). Survival increased among patients with shockable OHCA from 35% in 2001-2005 to 47.5% in 2016-2020 and among those with non-shockable OHCA from 6.4% in 2001-2005 to 10.1% in 2016-2020 (P<.001 for trend).

The study also found temporal improvement in prehospital resuscitation, defined as survival to hospital admission, 35.9% in 2001-2005 to 42.3% in 2016-2020 (P<.001 for trend) and in-hospital survival, defined as discharge among those admitted to hospital, 33.3% in 2001-2005 to 40.1% in 2016-2020 (P<.001 for trend). These improvements corresponded to temporal increases in bystander CPR, 55.5% from 2001-2005 to 73.9% from 2016-2020 (P<.001 for trend), and early automated external defibrillator application by non-EMS personnel, 2.2% in 2001-2005 to 10.9% in 2016-2020 (P<.001 for trend).

“[These] results suggest that the overall OHCA incidence did not change over time, although there were differential temporal patterns among clinical subgroups,” wrote the authors. “Survival improved over time overall and according to presenting rhythm, corresponding to favorable trends in community responder, prehospital, and hospital health services. Collectively, the findings underscore the ongoing public health challenge of OHCA and support the need to advance prevention and resuscitation strategies through rigorous science and evidence-based implementation.”

Disclosure(s):

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.