Sudden cardiac death as first manifestation of cardiovascular disease - a Danish nationwide study

Abstract Background and objective Sudden cardiac death (SCD) is a leading cause of death and previous studies have shown that approximately half of all cases have no known history of cardiovascular disease (CVD). Epidemiological studies of SCD cases of all ages are sparse. The aim of this study was to examine differences in incidence rates, clinical characteristics, comorbidities, and socioeconomic status between SCD cases with and without a known history of cardiovascular disease. Methods All 54,028 deaths in Denmark in 2010 were reviewed. Autopsy reports, death certificates, discharge summaries, and nationwide health and social registries were reviewed to identify cases of SCD. Information on previous history of CVD was extracted from the comprehensive Danish nationwide health and social registries. Results A total of 6,867 SCD cases were identified, of which 3,056 (44.5%) had no history of cardiovascular disease and 3,811 (55.5 %) had a history of CVD. Incidence rates of SCD increased with age and were higher in cases of SCD with a history of CVD across all age groups. The difference in incidence of SCD between persons with and without history of cardiovascular disease decreased with increasing age with incidence rate ratios ranging from 11.7 (95 % CI: 5.51 – 25.00) to 3.19 (95 % CI: 2.79-3.64) in those age 0-29 years and 90 years, respectively. Persons living in a low-income household (OR: 0.76, 95 % CI: 0.58-0.98, p=0.037), persons living in rural municipalities (OR: 0.87, 95 % CI: 0.78-0.98, p=0.021), and persons living in single-person households (OR: 0.73, 95 % CI: 0.66-0.82, p=0.037) had a lower likelihood of having a CVD prior to SCD. Conclusion This is the first nationwide study of SCD cases with and without history of CVD across all ages. SCD cases with no known CVD were significantly younger, more female and had less comorbidities. Although a substantial amount of SCD cases occur in persons with no known CVD, SCD is more common in the populations of persons with a history of CVD. Socioeconomic factors such as low income, living alone and living in rural communities were associated with a lower risk of having a cardiovascular diagnosis prior to SCD.Crude numbers and incidence rates of SCDIncidence rate ratios