Rising out-of-hospital mortality in Canada during 2020‒2022: A striking impact observed among young adults

Out-of-hospital mortality rates surged during the early COVID-19 pandemic. While expecting a return to pre-pandemic levels, the evolving patterns of out-of-hospital mortality in Canada remain uncertain. We investigated whether these rates returned to pre-pandemic levels.

This retrospective study, employing linked administrative data, analyzed out-of-hospital mortality trends among adult residents in Ontario, Alberta, and Nova Scotia. Interrupted time series analysis assessed trends in age- and sex-standardized rates/100,000/quarter during pre-pandemic (April 2014-March 2020) and pandemic periods (April 2020-March 2022), while considering April to June 2020 as the pandemic onset period. Crude mortality rates were also examined, stratified by sex and age groups.

Pre-pandemic, Ontario's standardized out-of-hospital mortality rates were rising, while Alberta's and Nova Scotia's remained stable. At the pandemic onset, all provinces experienced significant increases in standardized out-of-hospital mortality rates/100,000 (Ontario: β 14.6, 95% CI [3.97, 25.22]; Alberta: 21.3, 95% CI [9.26, 33.34]; Nova Scotia: 10.5, 95% CI [1.06, 19.88]). During the pandemic, standardized out-of-hospital mortality rates/100,000/quarter remained above pre-pandemic levels, with no significant departure from the increased pandemic onset levels (Ontario: - 1.6, 95% CI [- 3.63, 0.52]; Alberta: 0.45, 95% CI [- 1.47, 2.36]; Nova Scotia: - 0.06, 95% CI [- 2.18, 2.06]). Crude out-of-hospital mortality rates increased most prominently among individuals aged 18 to 45 in Alberta and Ontario, and among males across all provinces.

The sustained increase in out-of-hospital mortality, observed from the pandemic's onset, spanning more than 2 years, potentially suggests its persistent direct and indirect effects on population health in Canada.