Out-of-hospital Cardiac Arrest in Men and Women

Background: The incidence of sudden cardiac death is roughly 3 times greater in men than in women. However, in patients treated for out-of-hospital cardiac arrest, the relationships between sex and survival after adjustment for age and cardiac rhythm are unclear.

Methods And Results: In this retrospective cohort study, we examined 7069 men and 2582 women who were treated for out-of-hospital cardiac arrest in Seattle and suburban King County between 1990 and 1998. We compared successful prehospital resuscitation (hospital admission) and survival from event to discharge in men and women. Women had markedly reduced rates of ventricular fibrillation (VF), slightly older age, fewer witnessed arrests, and fewer arrests in public locations than men. Although their unadjusted resuscitation rate was lower (29% versus 32%, P<0.0001), women had a greater likelihood of resuscitation than men after adjustment for VF (odds ratio [OR] 1.13; 95% confidence interval [CI], 1.03 to 1.25) and after adjustment for VF plus additional factors (OR, 1.27; 95% CI, 1.14 to 1.41). The difference in resuscitation rates between men and women decreased as they aged (test for trend, P<0.0001). Unadjusted survival rates were also lower in women than in men (11% versus 15%, P<0.0001). Women had similar survival after adjustment for VF (OR, 0.97; 95% CI, 0.85 to 1.11) and after adjustment for VF plus additional factors (OR, 1.09; 95% CI, 0.93 to 1.27).

Conclusions: The lower unadjusted resuscitation and survival rates observed in women were primarily due to women's lower incidence of VF, a relatively favorable cardiac rhythm. After adjustment for VF and other factors, women had higher resuscitation rates than men, but similar rates of survival from event to discharge.