Sex differences in epidemiology, care, and outcomes in patients with out-of-hospital cardiac arrest in China.

BACKGROUND: Data on sex differences in out-of-hospital cardiac arrest (OHCA) are well described in developed countries, but scarce in developing countries. METHODS: This prospective, multicenter, population-based observational cohort study used data from the Baseline Investigation of Out-of-hospital Cardiac Arrest (BASIC-OHCA) study collected between January 1, 2020, and December 31, 2020. Differences in outcomes were assessed using multivariable hierarchical logistic regression, with prespecified subgroup analyses and interaction tests. RESULTS: The age-standardized incidence rate of emergency medical system (EMS)-treated OHCA was higher in males than in females (48.1 vs 20.8 per 100,000 person-years, IRR = 2.31, 95% CI: 2.26-2.36) in China. Among 33,650 EMS-treated OHCA patients, 10,793 (32.1%) were females. Females had less favorable resuscitation characteristics and prehospital care than males. In multivariable models, females had significantly higher odds of prehospital return of spontaneous circulation (adjusted odds ratio [OR] = 1.21, 95% CI: 1.06-1.38) and survival to hospital admission (adjusted OR = 1.33, 95% CI: 1.15-1.55). However, no significant sex difference was observed for survival to hospital discharge or 30 days (adjusted OR = 0.85, 95% CI: 0.66-1.10), or favorable neurological outcome (adjusted OR = 0.84, 95% CI: 0.62-1.14). In subgroup analyses, females had lower odds of survival and favorable neurological outcome than males among patients aged ≥50 years, those with shockable rhythm, and those without prehospital epinephrine administration. CONCLUSIONS: In China, females demonstrated better prehospital resuscitation outcomes. However, this early advantage was lost by discharge. These findings highlight the need for integrated evaluation across prehospital and in-hospital care to inform disparity-reduction strategies.