Regional Variation in Out-of-Hospital Cardiac Arrest Survival in the United States

Although previous studies have shown marked variation in out-of-hospital cardiac arrest survival across US regions, factors underlying this survival variation remain incompletely explained.Using data from the Cardiac Arrest Registry to Enhance Survival, we identified 96 662 adult patients with out-of-hospital cardiac arrest in 132 US counties. We used hierarchical regression models to examine county-level variation in rates of survival and...