Sex-specific differences in survival after out-of-hospital cardiac arrest: a nationwide, population-based observational study

BACKGROUND: It remains unclear whether men have more favorable survival outcomes after out-of-hospital cardiac arrest (OHCA) than women. METHODS: We reviewed a total of 386,535 patients aged ≥ 18 years with OHCA who were included in the Japanese registry from 2013 to 2016. The study endpoints were the rates of 1-month survival and neurologically intact survival (Cerebral Performance Category Scale score = 1 or 2). Based on age, the reviewed patients were categorized into the following eight groups: < 30, 30-39, 40-49, 50-59, 60-69, 70-79, 80-89, and ≥ 90 years. The survival outcomes in men and women were compared using hierarchical propensity score matching. RESULTS: The crude survival rate was significantly higher in men than in women in five groups: 30-39, 40-49, 50-59, 60-69, and 70-79 years (all P < 0.001). Similarly, the crude neurologically intact survival rate was significantly higher in men than in women in seven groups: < 30, 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89 years (all P < 0.005). However, multivariate logistic regression analysis of each group revealed no significant sex-specific differences in 1-month survival outcomes (all P > 0.02). Moreover, after hierarchical propensity score matching, the survival outcomes did not significantly differ between both sexes (all P > 0.05). CONCLUSIONS: No significant sex-specific differences were found in the rates of 1-month survival and neurologically intact survival after OHCA.