Abstract 3874: Sex Differences in Sudden Cardiac Death in the Cardiovascular Health Study
BACKGROUND: More women than men have died annually from ischemic heart disease since 1984, but women represent only one-third of sudden cardiac death (SCD) cases. Why women appear to be protected against SCD is unknown. We examined potential determinants of sex differences in the incidence of SCD and other heart disease deaths in the Cardiovascular Health Study (CHS) cohort. We hypothesized that women would be at lower risk of all cardiac deaths but that after adjustment for cardiovascular disease (CVD) risk factors and CVD burden, this gender difference would persist only for SCD and not for non-sudden heart disease deaths.
METHODS: CHS is an ongoing prospective cohort study of cardiovascular disease risk factors in 5,888 adults 65 years or older, who underwent extensive baseline and annual clinical examinations with follow-up for CV events and mortality. Cox regression was used to determine whether certain characteristics mediated the effect of sex on the risk of death. Outcomes of interest were all cause deaths, cardiac and noncardiac deaths as determined by the CHS events committee, and cardiac deaths further classified after cardiologist review as SCD or other heart disease deaths. In addition to sex, the final model included: age, diabetes, smoking, hypertension, HDL cholesterol, carotid intima media thickness, ECG QRS interval, and prevalent & incident myocardial infarction and congestive heart failure.
RESULTS: Men were at higher risk for all categories of death compared to women. In the final model, men remained at 2-fold higher risk for SCD, but only a nonsignficant 20% higher risk for other heart disease deaths.
CONCLUSIONS: Men have a higher risk of SCD compared to women after accounting for CVD risk factors and CVD burden. This suggests a possible sex based protective mechanism for SCD that may be biological or behavioral.