A five-year randomized controlled trial spanning 60 North Carolina counties found that a comprehensive community and emergency medical services education effort did not significantly improve survival with favorable brain function for adults who suffered cardiac arrest outside a hospital, according to late-breaking science presented at the American Heart Association's Scientific Sessions 2026 in Chicago and simultaneously published in NEJM.
The RACE-CARS intervention targeted the full chain of survival. It combined community-wide CPR training with an EMS component that trained 9-1-1 dispatchers to recognize cardiac arrest quickly and coach callers through CPR, plus enhanced first-responder efforts to increase defibrillation before EMS arrival. Training was free and delivered through schools, workplaces, county government and other community organizations.
Between July 2021 and June 2026, researchers randomly assigned 31 counties to receive the program while 29 continued existing practices. The counties represented roughly 8.5 million residents, nearly 80% of the state's population, and the study included 22,459 adults. About 9% of patients in intervention communities survived to hospital discharge with favorable brain function, compared with 9.4% in comparison communities. Bystanders performed CPR in 44.8% of intervention-community arrests versus 42.3% elsewhere, while defibrillation before EMS arrived occurred in 13.5% of intervention cases versus 15.3%.
The most notable signal came late. An exploratory analysis found that during the study's final year, people in program communities had 33% higher odds of receiving bystander CPR than those in non-intervention communities. "The increase in bystander CPR toward the end of the study shows there was some effect and suggests that a sustained community outreach may be needed to show an improvement in survival," said principal investigator Christopher Granger, M.D., FAHA, a cardiologist at Duke University.
Community partners conducted 5,724 CPR training events reaching 201,586 people, or 4.8% of residents in intervention counties, though participation ranged from more than 10% in four counties to fewer than 3% in eight. Of 405 trial-provided automated external defibrillator units, 26 of 31 counties deployed them. Limitations included uneven implementation, self-reported training data, 9-1-1 staffing shortages, the COVID-19 pandemic and Hurricane Helene.
The stakes are substantial. According to the 2026 Heart Disease and Stroke Statistics, about 350,000 Americans suffer out-of-hospital cardiac arrest annually and only about 1 in 10 survive. Survival odds fall roughly 10% for every minute without CPR, said study author Carolina Malta Hansen, M.D., Ph.D., of Copenhagen EMS. The 2025 Guideline for CPR and emergency cardiovascular care stresses rapid recognition, calling 9-1-1, starting CPR and using an AED, yet the Association's AED Fact Sheet notes only about 40% of out-of-hospital arrest victims receive bystander CPR.
The results carry implications for public health planners weighing costly, multi-year community campaigns. Through its Nation of Lifesavers initiative, the Association aims to double sudden cardiac arrest survival by 2030; the movement has raised U.S. bystander CPR confidence from 33% to 39% since 2023. Hansen said the public message remains simple: learn CPR, recognize the signs, call 9-1-1 and follow dispatcher instructions. The trial was funded by the National Institutes of Health and National Heart, Lung, and Blood Institute.
