Trends and Drivers of Declining Stroke Mortality in British Columbia: A Population-Based Study (2002-2022)

Stroke remains a leading cause of death in British Columbia (BC), Canada. Understanding whether mortality declines are driven by prevention (reduced incidence) or improved survival (treatment) can inform public health and acute care planning.

We conducted a population-based study of 123,075 stroke events from 2002 to 2022 among BC residents aged 35-110 years, using linked administrative datasets. We calculated age-standardized rates of stroke events, 30-day case fatality and mortality, stratifying the rates by sex, age, income and geography. Regression models estimated temporal changes and relative contributions of declining event rates and case fatality to mortality reductions.

Age-standardized stroke event rates declined by 33% in females (208-140 per 100,000) and 25% in males (248-187) but increased among adults aged 35-54 (+14% females, +27% males). Females experienced a higher burden of stroke events as pre-admission deaths, particularly among 85+. Case fatality fell by 22% in females (40-31 per 100 events) and 15% in males (37-32), with the greatest improvements in younger adults. Mortality declined by 53% in females (72-34 per 100,000) and 43% in males (72-41) primarily driven by declines in case fatality. Disparities by sex, income and geography persisted.

Improved survival is the main driver of declining stroke mortality in BC, particularly in recent years. Socioeconomic, sex and age disparities persist, warranting focused strategies to address inequities and the rising stroke burden among younger populations.