Sex differences in OHCA outcomes are driven by arrest circumstances rather than different EMS treatment: a nationwide...

Studies on sex-disparities in out-of-hospital cardiac arrest (OHCA) show conflicting results. This study seeks to identify if there are sex-based disparities in prehospital treatment and survival in out-of-hospital cardiac arrests in Norway.

This is a retrospective 10-year cohort study from the Norwegian Cardiac Arrest Registry (NorCAR). We examined sex in relation to clinically important variables such as bystander cardiopulmonary resuscitation, use of defibrillator, survived event and survival to 30 days. We conducted multivariable regression analysis to examine associations between sex and survival outcomes.

During the years 2015-2024 NorCAR collected 27,621 cases of EMS-treated OHCA. Women comprised 32% of the cohort. Women presented with cardiac arrest at different locations than men and had significantly lower rates of initial shockable rhythm. We found differences in treatment related to cardiopulmonary resuscitation (CPR) duration, use of advanced airway and use of adrenalin. We observed higher rates of bystander CPR for women compared to men. When adjusting for known covariates, we found a higher Odds Ratio (OR) of survived event for women, but survival to 30 days was lower.

We found differences in baseline characteristics and treatment performed by Emergency Medical Services (EMS) between women and men, as well as differences in survived event and survival to 30 days. Differences in EMS treatment did not seem to be related to the patient's sex. We did, however, find sex differences in survived event and survival to 30 days unexplained by our included variables.