Sudden Cardiac Death as First Manifestation of Cardiovascular Disease: A Nationwide Study of 54,028 Deaths

BACKGROUND: Sudden cardiac death (SCD) is a significant public health problem. Knowledge on SCD victims without a history of cardiovascular disease (CVD) is limited, presenting challenges for future prevention efforts.

OBJECTIVES: This study aims to examine the differences between SCD cases with and without a known history of CVD.

METHODS: All Danish citizens were followed from January 1, 2010, until death or the end of the year. All deaths in Denmark during this period were reviewed by ≥1 medical doctor to identify cases of SCD. Data were analyzed from March 2023 until March 2024.

RESULTS: A total of 6,851 SCD cases were identified, of which 3,046 (44.5%) had no history of CVD. Incidence rates of SCD increased with age and were higher in cases with a history of CVD across all age groups. The difference in SCD incidence between individuals with and without a history of CVD decreased with age, with incidence rate ratios ranging from 21.6 (95% CI: 5.2-66.7) in those aged 0 to 19 years to 1.8 (95% CI: 1.7-1.9) in those aged >90 years. Female sex and living alone were associated with a lower odds of having a CVD before SCD with ORs of 0.66 and 0.75, respectively.

CONCLUSIONS: The distribution of SCD cases is nearly equal between individuals with and without a history of CVD, although the risk remains higher in those with prior CVD. Future research should aim to uncover the distinct causes and mechanisms driving SCD in populations with a known CVD, as well as the general population.