Nationwide study on sudden cardiac death in Danes aged 1-49 years

Purpose: Incidence rates and causes of sudden cardiac death (SCD) in the young have varied markedly in previous studies. The aim of this first nationwide study was to identify the causes of SCD in persons aged 1-49 years and to estimate the incidence rate using both autopsied and non-autopsied cases. Methods: All deaths in persons aged 1-49 years in 2007-2009 were included (population 3.4 million). Death certificates were reviewed independently and SCD cases were identified. We defined SCD in autopsied cases as the sudden, natural unexpected death of cardiac or unknown cause; in unwitnessed cases as a person last seen alive and functioning normally <24 h and in witnessed cases as an acute change in cardiovascular status with time to death being <1 h. In non-autopsied cases the same criteria were used in cases presumed to be of cardiac cause. The highest possible incidence of SCD was calculated using both autopsied and non-autopsied cases. Results: In the 3-year study-period there were 7,849 deaths of which we identified 1,039 (13%) presumed SCDs, of which 585 (56%) were autopsied. Autopsies showed that death was non-cardiac in 146 cases. Hence, we identified 439 autopsied SCDs and 454 non-autopsied SCDs. The most common cardiac cause of death was ischaemic heart disease (IHD) (n=158, 36%). In 136 cases (31%) death was unexplained (SUD) after autopsy with fatal arrhythmia being the presumed cause of death. The SCD incidence was 8.6 per 100,000 person-years using both autopsied and non-autopsied cases. For age distribution, see figure. Distribution of 893 SCDs aged 1-49 Conclusion: This is the first nationwide study describing the highest possible incidence of SCD in persons aged 1-49 years. We report a incidence of SCD of 8.6 per 100,000 person-years with IHD and SUD being the most common causes of SCD