Association between county-level cardiopulmonary resuscitation training and changes in Survival Outcomes after out-of-hospital cardiac arrest over 5 years: A multilevel analysis

Abstract

Introduction: Associations between neighbourhood environments and survival outcomes after out-of-hospital cardiac arrests (OHCAs) have been proposed. The purpose of this study was to examine the association between county-level cardiopulmonary resuscitation (CPR) training rates and improvements in survival outcomes after OHCA over 5 years.

Methods: Emergency medical service (EMS)-treated OHCAs with cardiac etiology between 2012 and 2016 were analyzed, excluding cases witnessed by EMS providers. The main exposure of interest was county-level CPR training rate defined as the proportions of residents having received CPR training, which was measured in 2016. The endpoint was survival with good neurological recovery. We compared the differences between outcomes from 2012 and 2016 according to quartile groups of counties by the CPR training rates using a difference-in-differences design.

Results: A total of 81,250 OHCAs in 254 counties were analyzed. The risk-adjusted good neurological recovery rates increased from 5.4% in 2012 to 7.1% in 2016 (adjusted rates difference: 1.6% (1.2-2.1)). The OHCAs that occurred in counties with the highest county-level CPR training rates were more likely to survive with good neurological recovery (adjusted rates: 5.2% in 2012 and 7.4% in 2016, difference: 2.2% (1.5-2.9)) than were those occurring in the lowest county-level CPR training counties (adjusted rates: 5.9% in 2012 and 6.0% in 2016, difference: 0.1% (-1.1 to 1.2)). The difference-in-differences was 2.1% (0.8-3.5).

Conclusions: There were moderate associations between county-level CPR training and improvements in good neurological recovery rates over 5 years in the counties.

Keywords: Bystander cardiopulmonary resuscitation; Out-of-hospital cardiac arrest; Survival.