Women have lower chances thanmen to be resuscitated and survive out-of-hospital cardiac arrest

Aims:
Previous studies on sex differences in out-of-hospital cardiac arrest (OHCA) had limited scope and yielded conflicting
results. We aimed to provide a comprehensive overall view on sex differences in care utilization, and outcome
of OHCA.

Methods and results:
We performed a population-based cohort-study, analysing all emergency medical service (EMS) treated resuscitation
attempts in one province of the Netherlands (2006–2012). We calculated odds ratios (ORs) for the association of
sex and chance of a resuscitation attempt by EMS, shockable initial rhythm (SIR), and in-hospital treatment using logistic
regression analysis. Additionally, we provided an overview of sex differences in overall survival and survival at
successive stages of care, in the entire study population and in patients with SIR. We identified 5717 EMS-treated
OHCAs (28.0% female). Women with OHCA were less likely than men to receive a resuscitation attempt by a bystander
(67.9% vs. 72.7%; P < 0.001), even when OHCA was witnessed (69.2% vs. 73.9%; P < 0.001). Women who
were resuscitated had lower odds than men for overall survival to hospital discharge [OR 0.57; 95% confidence
interval (CI) 0.48–0.67; 12.5% vs. 20.1%; P < 0.001], survival from OHCA to hospital admission (OR 0.88; 95% CI
0.78–0.99; 33.6% vs. 36.6%; P = 0.033), and survival from hospital admission to discharge (OR 0.49, 95% CI 0.40–
0.60; 33.1% vs. 51.7%). This was explained by a lower rate of SIR in women (33.7% vs. 52.7%; P < 0.001). After
adjustment for resuscitation parameters, female sex remained independently associated with lower SIR rate.

Conclusion:
In case of OHCA, women are less often resuscitated by bystanders than men. When resuscitation is attempted,
women have lower survival rates at each successive stage of care. These sex gaps are likely explained by lower
rate of SIR in women, which can only partly be explained by resuscitation characteristics.