# Population-based risk adjusted outcomes for out-of-hospital cardiac arrest

## TL;DR

This study examines survival rates after out-of-hospital cardiac arrest across the US and identifies regional disparities influenced by population and hospital characteristics.

## Contribution

A population-based risk adjustment model was applied to Medicare data to identify regional OHCA survival disparities and associated factors.

## Key findings

- Nearly half of the regions had lower-than-expected OHCA survival rates after risk adjustment.
- Overperforming regions had smaller populations, older demographics, and more large hospitals.
- Cardiac catheterization capability was inversely associated with improved survival in these regions.

## Abstract

Out-of-hospital cardiac arrest (OHCA) impacts public health, with variable survival across the US. This study used a population-based risk adjustment model to understand factors influencing regional variability in OHCA survival to hospital discharge. We evaluated 202,406 OHCA cases from 2013-2015 Medicare Fee-For-Service claims across 205 hospital regions. A matched cohort from the Cardiac Arrest Registry to Enhance Survival (CARES) and Medicare claims was used to develop logistic regression models predicting survival. Standardized Incidence Ratios (SIRs) identified regions performing better or worse than expected. Of 205 regions, 101 (49.3%) demonstrated lower-than-expected risk-adjusted survival, while only 9 (4.4%) had higher-than-expected survival. Overperforming regions had smaller populations, higher proportions of residents aged 65 + , and more large hospitals (400+ beds). Hospitals with ≥100 beds were more likely in overperforming regions, while cardiac catheterization capability showed inverse association. These nationwide disparities highlight the need for targeted interventions and regionalized care approaches to improve survival rates.