Gender-Based Differences in Outcomes among Resuscitated Patients with Out-of-Hospital Cardiac Arrest

Background: Studies examining gender-based differences in outcomes of patients experiencing out-of-hospital cardiac arrest have demonstrated that, despite a higher likelihood of return of spontaneous circulation, women do not have higher survival. Methods: Patients successfully resuscitated from out-of-hospital cardiac arrest enrolled in the CCC trial (Trial of Continuous or Interrupted Chest Compressions during CPR) were included. Hierarchical multivariable logistic regression models were constructed to evaluate the association between gender and survival after adjustment for age, gender, cardiac arrest rhythm, witnessed status, bystander cardiopulmonary resuscitation, episode location, epinephrine dose, emergency medical services response time, and duration of resuscitation. Do not resuscitate (DNR) and withdrawal of life-sustaining therapy (WLST) order status were used to assess whether differences in postresuscitation outcomes were modified by baseline prognosis. The analysis was replicated among ALPS trial (Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest) participants. Results: Among 4875 successfully resuscitated patients, 1825 (37.4%) were women and 3050 (62.6%) were men. Women were older (67.5 versus 65.3 years), received less bystander cardiopulmonary resuscitation (49.1% versus 54.9%), and had a lower proportion of cardiac arrests that were witnessed (55.1% versus 64.5%) or had shockable rhythm (24.3% versus 44.6%, P<0.001 for all). A significantly higher proportion of women received DNR orders (35.7% versus 32.1%, P=0.009) and had WLST (32.8% versus 29.8%, P=0.03). Discharge survival was significantly lower in women (22.5% versus 36.3%, P<0.001; adjusted odds ratio, 0.78 [95% CI, 0.66-0.93]; P=0.005). The association between gender and survival to discharge was modified by DNR and WLST order status such that women had significantly reduced survival to discharge among patients who were not designated DNR (31.3% versus 49.9%, P=0.005; adjusted odds ratio, 0.74 [95% CI, 0.60-0.91]) or did not have WLST (32.3% versus 50.7%, P=0.002; adjusted odds ratio, 0.73 [95% CI, 0.60-0.89]). In contrast, no gender difference in survival was noted among patients receiving a DNR order (6.7% versus 7.4%, P=0.90) or had WLST (2.8% versus 2.4%, P=0.93). Consistent patterns of association between gender and postresuscitation outcomes were observed in the secondary cohort. Conclusions: Among patients resuscitated after experiencing out-of-hospital cardiac arrest, discharge survival was significantly lower in women than in men, especially among patients considered to have a favorable prognosis.