Objective: Studies evaluating a possible survival advantage from sudden cardiac arrest (SCA) in women have produced mixed results possibly due to a lack of comprehensive analyses. We hypothesized that race, socioeconomic status (SES), and elements of the lifetime clinical history influence gender effects and need to be incorporated within analyses of survival.
Methods: Cases of SCA were identified from the ongoing, prospective, multiple-source Oregon Sudden Unexpected Death Study (population approximately one million). Subjects included were age ≥18 years who underwent attempted resuscitation by EMS providers. Pearson's chi-square tests and independent samples t tests or analysis of variance were used for univariate comparisons. We evaluated gender and race differences in survival adjusted for age, circumstances of arrest, disease burden, and socioeconomic status using a logistic regression model predicting survival.
Results: A total of 1,296 cases had resuscitation attempted (2002-2007; mean age 65 years, male 67%). Women were older than men (68 vs. 63 years, p < 0.0001) and were more likely to have return of spontaneous circulation (41% vs. 33%, p = 0.004). Women were more likely to present with pulseless electrical activity (PEA) and asystole (p < 0.0001), and overall, PEA was more common among African Americans (p = 0.04). Higher survival to hospital discharge was observed in women compared to men presenting with ventricular fibrillation/tachycardia (34% vs. 24%, p = 0.02) or with PEA (10% vs. 3%, p = 0.007). In a multivariate model adjusting for age, race, presenting arrhythmia, arrest circumstances, arrest location, disease burden, and SES, women were more likely than men to survive to hospital discharge [odds ratio 1.85; 95% confidence interval (1.12-3.04)].
Conclusions: Despite older age, higher prevalence of SCA in the home, and higher rates of PEA, women had a survival advantage from ventricular fibrillation and pulseless electrical activity.