Sex differences in sudden cardiac death: a nationwide study of 54,028 deaths in Denmark

Abstract Background Sudden cardiac death (SCD) is a leading cause of death. SCD is more common among males. In women SCD is, however, still the leading cause of death. The SCD epidemiology among women is less studied. Purpose The aim of this study was to examine how incidence rates, clinical characteristics and causes of SCD vary between males and females. Methods All deaths in Denmark in the 2010 (54,028) were included in the study. Autopsy reports, death certificates, discharge summaries and nationwide health registries were reviewed to identify cases of SCD. Sex and age specific SCD incidence rates in the general population were calculated, and age-adjusted clinical characteristics were compared using logistic regression. Results A total of 6,867 SCD cases were identified, of which 3,859 (56%) were males and 3,008 (44%) were females. Incidence rates increased with age and was higher for males across all age groups in the adult population. Average age of SCD was 71.3±14.3 years among males compared to 79.4±13.3 among females (mean ± standard deviation, p<0.0001). The greatest difference in incidence between males and females was found among the 35–50-year group with an incidence rate ratio of 3.7 (95% confidence interval: 2.8–4.8). Although the males were younger, males more often had cardiovascular diseases and diabetes mellitus prior to SCD. Among autopsied cases, coronary artery disease (CAD) was the leading cause of death among both sexes. Structural causes of SCD, other than CAD, were more common among women (p<0.01). Conclusion In this nationwide study of sex differences in SCD across all age groups, the differences in incidence rates between males and females were greatest among young adults and the middle-aged. Incidence rates of SCD among older females approached that of the male population, despite significantly more cardiovascular disease and diabetes mellitus in the male population in the 10 years prior to SCD. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark