Differences among young unwitnessed sudden cardiac death, according to time from last seen alive: Insights from a 15-year nationwide study

Abstract

More than half of all sudden cardiac deaths (SCD) are unwitnessed, but the composition of the unwitnessed SCD population is poorly described. This study aimed to compare clinical and autopsy characteristics of young unwitnessed SCD, depending on the time from last contact to being found dead. All unwitnessed SCD aged 1-35 years in Denmark from 2000-2014 identified through a multi-source approach were included. Time from last seen alive to being found dead was dichotomized in <1 hour or 1-24 hours. Clinical characteristics and autopsy results were compared, and predictors of autopsy were assessed by logistic regression. Of 440 unwitnessed SCD, 366 (83%) had not been seen alive within one hour of being found dead. Comorbidities differed between the groups with more epilepsy (17% vs 5%) and psychiatric diseases (13% vs 7%) in the 24-hour group. The 24-hour group died more frequently during sleep (64% vs 23%), the autopsy rate was higher (75% vs 61%), and deaths were more often unexplained after autopsy (69% vs 53%). Having been seen within one hour of death independently decreased the chance of being autopsied with OR 0.51 [95% CI 0.27-1.00, p = 0.0497]. The majority of unwitnessed SCD had not been seen alive within one hour of being found dead. Clinical- and autopsy-related characteristics differed among the two groups. Differences were mainly attributable to death-related circumstances and comorbidities. Excluding SCD cases not seen alive within one hour of being found dead would severely underestimate the burden of SCD.