Sex-Specific Differences in Survival After Out-of-Hospital Cardiac Arrest

A Nationwide, Population-Based Observational Study

Yoshikazu Goto; Akira Funada; Tetsuo Maeda; Hirofumi Okada; Yumiko Goto


Crit Care. 2019;23(263) 

In This Article


Location of arrest, younger age, presence of witnesses, bystander cardiopulmonary resuscitation (CPR), initial shockable rhythm, early defibrillation, short CPR duration, short emergency medical service (EMS) response time, and prompt coronary angiography with percutaneous coronary intervention if indicated are factors reportedly associated with survival in patients with out-of-hospital cardiac arrest (OHCA).[1–5] In terms of sex differences related to patient outcomes after OHCA, some studies reported that compared with men of the same age, women of childbearing age were independently associated with improved survival;[6–14] this survival advantage might be attributable to the protective anti-apoptotic, anti-inflammatory, and mitochondria-stabilizing activities of estrogen.[6,12,15] Other studies failed to demonstrate such an advantage but instead reported equal or worse survival rates or lower quality of life among female OHCA survivors.[16–21] Inconsistent results reported by previous observational studies may be due to differences in the study populations, EMS systems, and patient risk factors. A previous study reported differences in the baseline characteristics of women and men with OHCA. Compared with the women, the men were reportedly younger, and arrest was more frequently witnessed in the men than in the women; bystander CPR, cardiac etiology, and initial shockable rhythm were also more frequent in the men than in the women.[12] Rigorous statistical analysis is needed to confirm the differences in outcomes after OHCA between women and men. Therefore, in the present study, hierarchical propensity score matching was used to analyze and compare the outcomes after OHCA between age-stratified women and men who were included in a Japanese registry.