Temporal trends in sudden cardiac death in Ontario, Canada

Although the prevention and treatment of cardiovascular conditions have significantly improved over the past decade, whether they have reduced the incidence of sudden cardiac death (SCD) is not known. We sought to evaluate the temporal trends of SCD in a large unselected population.

We conducted a population-based cohort study using multiple linked longitudinal data in Ontario Canada. We included patients aged 35-74 years who had SCD from April 1st 2003 to March 31st 2014. SCD was defined as those who died of cardiac causes outside of the hospital or the emergency department, and had no recent hospitalization, no serious illness, and who were not residing in long-term care facilities.

We identified 36,334 patients who fulfilled criteria for SCD. The overall age and sex-standardized rate of SCD declined from 57.9/100,000 in fiscal year 2003 to 42.4/100,000 in 2013. Men and women had similar declining trends in SCD incidence. Larger reductions were seen among the older age groups. Patients who had prior heart failure experienced the largest decline in SCD incidence from 829/100,000 to 533/100,000 from 2003 to 2013. Patients who had prior myocardial infarction also had significant reduction from 484/100,000 to 381/100,000. In contrast, individuals with cardiac risk factors without disease had much smaller declines in SCD incidence.

Although significant progress to reduce SCD among patients with cardiac conditions was made in the past decade, additional effort should focus on the prevention of SCD in individuals without heart disease.