Sex differences in the association between bystander CPR and survival for Out-of-Hospital cardiac arrest

Background: Prior studies have identified socio-cultural barriers in laypersons performing high-quality cardiopulmonary resuscitation (CPR) in women. Whether the effect of layperson bystander CPR on survival from out-of-hospital cardiac arrest (OHCA) differs by patients' sex is unknown.

Methods: Using data during 2013-2020 from an OHCA registry in the U.S., we identified adult patients with non-traumatic OHCA. The primary outcome was favorable neurological survival and the secondary outcome was survival to discharge. Multivariable logistic regression models evaluated the interaction between patients' sex and bystander CPR with survival, adjusted for patient and cardiac arrest characteristics.

Results: Of 420,671 patients with OHCA, 151,145 (35.9 %) occurred in women and 269,526 (64.1 %) in men. Rates of layperson bystander CPR were similar between women (38.3 %) and men (40.0 %). Rates of favorable neurological survival were 11.4 % in those with bystander CPR and 5.6 % in those without, but the association between bystander CPR and favorable neurological survival was weaker for women than men (women: adjusted OR, 1.33 [95 % CI: 1.27-1.39]; men: adjusted OR, 1.55 [95 % CI: 1.51-1.61]; interaction p < 0.001)]. Rates of survival to discharge were 13.1 % and 7.3 % in those with and without layperson bystander CPR, and the association between bystander CPR was weaker for women than men (women: adjusted OR, 1.21 [95 % CI: 1.16-1.26]; men: adjusted OR, 1.43 [95 % CI: 1.39-1.47]; interaction p < 0.001).

Conclusions: For OHCA, bystander CPR was associated with higher survival in women and men. However, as currently practiced, the association between bystander CPR and higher survival was weaker for women as compared with men.