More than half of all sudden cardiac deaths occur in persons without a history of cardiovascular disease: A study of 54,028 deaths in Denmark

Abstract

Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Copenhagen University Hospital, Rigshospitalet Background Sudden cardiac death (SCD) is a major public health problem accounting for a large proportion of global mortality. Previous studies suggest that SCD often occurs in the general population in persons not previously diagnosed with cardiovascular disease. It is evidently challenging to identify high-risk persons in an overwhelmingly large population of mainly healthy individuals and studies are needed to further characterize these SCD cases. Purpose To estimate SCD burden in patients not previously diagnosed with cardiovascular disease and to characterize these SCD cases. Methods All deaths in Denmark (population of 5.5 million) in 2010 were manually reviewed case-by-case. Autopsy reports, death certificates, and information from nationwide health registries were systematically examined to identify all SCD in 2010. The Danish National Patient Register contains information on all in- and outpatient activities at Danish hospitals and emergency departments and was used to identify all SCD cases with a previous cardiovascular diagnosis. Results There were 54,028 deaths in Denmark in 2010, of which 6,867 (13%) were categorized as SCD. Overall incidence rate of SCD was 124 (95%-CI: 121-127) per 100,000 person-years. Of all SCD, 59% were not diagnosed with cardiovascular disease prior to death. SCD incidence in persons with and without a history of cardiovascular disease was 790 (95%-CI: 762-820) and 78 (95%-CI: 75-80) per 100,000 person-years, respectively. This corresponds to an incidence rate ratio of 10 (95%-CI: 10-11). SCD cases with no previously diagnosed cardiovascular diseases were younger (median age 75 vs. 80 years, p<0.001), more often female (45 vs. 42%, p=0.019), and on average had a lower household income (p=0.002) (Table 1). SCD cases not diagnosed with cardiovascular disease prior to death in general had fewer comorbidities, except for psychiatric diseases, which were more common in the undiagnosed group (Table 1). Conclusion In this large and nationwide study of all SCD in Denmark in 2010, more than half of all SCD occurred in persons without a history of cardiovascular disease. This suggests that SCD is often first manifestation of disease. We currently do not have accurate tools for SCD risk stratification in the general population and future research is needed to identify modifiable and easily measured risk factors of SCD in the general population.