Sex differences among patients presenting to hospital with out-of-hospital cardiac arrest and shockable rhythm

Objective: Sex differences in patients presenting with out-of-hospital cardiac arrest (OHCA) and shockable rhythm might be associated with disparities in clinical outcomes. Methods: We conducted a retrospective cohort study and compared characteristics and short-term outcomes between male and female adult patients who presented with OHCA and shockable rhythm at two large metropolitan health services in Melbourne, Australia between the period of 2014–2018. Logistic regression was used to assess the effect of sex on clinical outcomes. Results: Of 212 patients, 166 (78%) were males and 46 (22%) were females. Both males and females presented with similar rates of ST-elevation myocardial infarction (44% vs 36%, P = 0.29), although males were more likely to have a history of coronary artery disease (32% vs 13%) and a final diagnosis of a cardiac cause for their OHCA (89% vs 72%), both P = 0.01. Rates of coronary angiography (81% vs 71%, P = 0.23) and percutaneous coronary intervention (51% vs 42%, P = 0.37) were comparable among males and females. No differences in rates of in-hospital mortality (38% vs 37%, P = 0.90) and 30-day major adverse cardiac and cerebrovascular events (composite of all-cause mortality, myocardial infarction, coronary revascularization and nonfatal stroke) (39% vs 41%, P = 0.79) were observed between males and females, respectively. Female sex was not associated with worse in-hospital mortality when adjusted for other variables (odds ratio 0.66, 95% confidence interval 0.28–1.60, P = 0.36). Conclusion: Among patients presenting with OHCA and a shockable rhythm, baseline sex and sex differences were not associated with disparities in short-term outcomes in contemporary systems of care.