Sex differences in outcomes for out-of-hospital cardiac arrest in the United States

Abstract

Background: Approximately 1000 out-of-hospital cardiac arrest (OHCA) occur each day in the United States. Although sex differences exist for other cardiovascular conditions such as stroke and acute myocardial infarction, they are less well understood for OHCA. Specifically, the extent to which neurological and survival outcomes after OHCA differ between men and women remains poorly characterized in the U.S.

Methods and results: Within the national Cardiac Arrest Registry to Enhance Survival (CARES) registry, we identified 326,138 adults with an OHCA from 2013 to 2019. Using multivariable logistic regression, we evaluated for sex differences in rates of survival to hospital admission, survival to hospital discharge, and favorable neurological survival (i.e., without severe neurological disability), adjusted for demographics, cardiac arrest characteristics and bystander interventions. Overall, 117,281 (36%) patients were women. Median age was 62 and 65 years for men and women, respectively. An initial shockable rhythm (25.1% vs 14.7%, standardized difference of 0.26) and an arrest in a public location (22.2% vs. 11.3%; standardized difference of 0.30) were more common in men, but there were no meaningful sex differences in rates of witnessed arrests, bystander cardiopulmonary resuscitation, intra-venous access, or use of mechanical devices for delivering cardiopulmonary resuscitation. Overall, the unadjusted rates of all survival outcomes were similar between men and women: survival to hospital admission (27.0% for men vs. 27.9% for women, standardized difference of -0.02), survival to hospital discharge (10.5% for men vs. 8.6% for women, standardized difference of 0.07), and favorable neurological survival (9.0% for men vs. 6.6% for women, standardized difference of 0.09). After multivariable adjustment, however, men were less likely to survive to hospital admission (adjusted OR = 0.75, 95% CI: 0.73, 0.77), survive to hospital discharge (adjusted OR = 0.83, 95% CI: 0.80, 0.85), or have favorable neurological survival (adjusted OR = 0.88, 95% CI: 0.85, 0.91).

Conclusions: Compared to women, men with OHCA have more favorable cardiac arrest characteristics but were less likely to survive to hospital admission, survive to discharge, nor have favorable neurological survival.

Keywords: Epidemiology; Neurological outcomes; Out-of-hospital cardiac arrest; Sex differences; Survival outcomes.

Figure 1.. Consort Diagram Showing the Final Analytic Sample

**Completed cases are those that had complete record of age, sex, shockable, witnessed arrest, BCPR, AED, location, year of arrest and survival (survival to hospital admission, survival to hospital discharge and neurological survival). The categories are excluded in sequence. First, ages<18 were excluded, then all 911 witnessed arrests and then the nursing homes were excluded from the complete data.

Figures 2a-c.

Predicted Probabilities for Men and Women across the Age Spectrum for each Outcome Measure