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

This nationwide Danish study examined 54,028 sudden cardiac deaths over a defined period to characterize how many occurred as the first clinical manifestation of cardiovascular disease — with no prior known CVD diagnosis — and to identify associated factors.

Nearly half of all sudden cardiac death victims (44.5%, or 3,046 of 6,851 analyzed cases) had no prior documented cardiovascular disease history at the time of death. This proportion was highest in younger patients: the incidence rate ratio of SCD in patients with known CVD versus no prior CVD was 21.6 among those aged 0–19, declining to 1.8 for those over 90 — reflecting that young SCD disproportionately occurs outside the recognized CVD population. Female sex and living alone were associated with lower odds of having prior CVD before SCD.

The central clinical implication is uncomfortable: current cardiovascular prevention strategies are largely targeted at patients with identified risk factors and established disease. But nearly half of all SCDs occur in people with no prior clinical warning. Standard risk stratification fails this population, and current prevention frameworks — focused on identified patients — cannot reach them.

This finding supports the case for population-level primary prevention: earlier universal risk assessment, wider deployment of CAC scoring and cardiac biomarkers in asymptomatic individuals, and genetic risk screening — all aimed at identifying the subclinical CAD that will become the fatal coronary event before it declares itself.

We rate the evidence strong. A large nationwide population study establishing that nearly half of all sudden cardiac deaths occur as the first clinical manifestation of CVD — a fundamental argument for expanding upstream prevention well beyond diagnosed patients.