Comparison of out-of-hospital mortality following injury in Canadian provinces and territories: a historical cohort study.

Objective: Trauma systems encompass injury prevention, prehospital care, acute care, rehabilitation, and community integration. The proportion of out-of-hospital injury deaths may indicate the effectiveness of trauma systems, particularly in prevention and prehospital care. In the absence of Canadian data, we aimed to estimate this proportion nationally and by province and analyze variations by age, sex, and year.

Methods: We conducted a historical cohort study to analyze aggregate data on hospital discharges and mortality statistics covering injury-related deaths in Canadian provinces and territories from 2017 to 2020. We included deaths from all Canadian provinces and territories except Quebec, for which data on in-hospital deaths were unavailable. We calculated the proportions of out-of-hospital deaths with 95% confidence intervals. We used robust Poisson models to assess provincial variation, adjusting for age, sex, and year for Ontario, Alberta, and British Columbia (the volumes were too low in the other provinces). We conducted subgroup analyses for age group, sex, year, and injury mechanism.

Results: Canada recorded 64,725 injury-related deaths between 2017 and 2020 (32.3% ≥ age 65 yr; 34.5% female), with 48% occurring outside of hospitals globally and 80% in < 65-yr-olds. Proportions of out-of-hospital deaths ranged from 30% in the Atlantic provinces to 58% in Saskatchewan. After adjusting for age, sex, and year, Alberta had a 13% higher risk of out-of-hospital mortality than Ontario (reference standard), while British Columbia had a 26% lower risk. Subgroup analyses revealed variations across age groups, sex, and years.

Conclusions: Half of all injury deaths in Canada between 2017 and 2020 occured outside of hospitals. This proportion varied by province, possibly suggesting differences in the development and maturity of provincial trauma systems. Future studies should strive to identify modifiable determinants of these interprovincial variations to inform public health strategies.