Sex differences in outcome after ventricular fibrillation in out-of-hospital cardiac arrest

INTRODUCTION: Previous studies have shown that early defibrillation programs improve survival after an out-of-hospital cardiac arrest (OHCA). Reports also suggest that women fare worse than men do after cardiovascular events, but there is no population-based study of sex differences after an OHCA with early defibrillation. We, therefore, compared the short- and long-term survival and quality-of-life (QOL) in women and men after an OHCA. METHODS: All patients with a ventricular fibrillation (VF) OHCA who received early defibrillation in Olmstead County, Minnesota between November 1990 and December 2000 were included. Using medical records and the cardiac arrest database, the short- and long-term survival and QOL based on a SF-36 survey of each sex were compared. Adjusted QOL scores were obtained by using age- and sex-specific norms from a sample of the general U.S. population; an adjusted score of 50 (normalized mean) was considered normal. RESULTS: Thirty-seven female and 163 male patients presented with a VF OHCA and early defibrillation. Survival to hospital admission was significantly better for women than men [30 female survivors to admission (81%), 112 male (69%), p = 0.04]. Paradoxically, survival to discharge among those admitted was worse for women [13 female survivors to discharge (43%), 66 male (61%), p = 0.04]. The average length of follow-up was 4.8+/-3.0 years. The 5-year expected survival was 83% in women and 78% in men (p = 0.48). There was no difference in call-to-shock time (6+/-2, 6+/-2 min, p = 0.6) or whether the arrest was witnessed (86, 82%, p = 0.64). There was no statistical difference between women and men in age (64+/-17, 65+/-14 years), ejection fraction (40+/-17, 40+/-18%), diabetes (17, 29%, p = 0.16), hypertension (23, 28%, p = 0.58) or known CAD (27, 48%, p = 0.06). Adjusted QOL scores were similar between women and men in terms of pain (52+/-9, 52+/-10) vitality (47+/-11, 40+/-9), general health (49+/-9, 44+/-7), social function (51+/-10, 51+/-8), and mental health (50+/-10, 49+/-6). CONCLUSION: Women are more likely to survive to hospital admission following an OHCA. However, admitted women less likely to survive their hospital stay. Long-term survival and QOL are equally favorable in both sexes.