Health services use for injury amongst persons experiencing homelessness in Ontario, Canada: a population-based retrospective matched cohort study

Background — Homelessness is an increasingly prevalent public health concern and an important determinant of mental and physical health. The relationships between housing status and injury incidence and outcome are poorly understood. In this study we sought to both establish the epidemiology of injury amongst persons experiencing homelessness (PEH) and to determine the association between the experience of homelessness and utilization of acute care health services for injuries.

Methods — We conducted a retrospective matched cohort study including adults experiencing homelessness between April 1, 2021 and March 31, 2023, along with unexposed (presumed housed) patients age and sex matched to the exposed group 4:1. Groups were followed over one year to identify emergency department visits and inpatient hospitalizations for injury. Secondary outcomes included intent of injury, mechanism of injury, and discharge disposition for hospitalized individuals. We used multivariate regression to compare the rates of health services use between the cohorts, after adjusting for income quintile, rurality, and comorbidity burden.

Results — The cohort consisted of 220,740 individuals, including 44,148 PEH. The experience of homelessness was associated with a significantly higher rate of emergency department utilization (Adjusted RR: 1.60, 95% CI: 1.56–1.64) and hospitalization (Adjusted RR: 3.77, 95% CI: 3.53–4.01) for injury. PEH had particularly pronounced rates of injury related to self- harm, assault, fire/burns and firearms, as well as significantly longer hospitalization length and higher rates of self-discharge.

Conclusion — PEH are at greater risk of injury requiring acute care health services, particularly for injuries due to self-harm, assault, and violence. Further research should prioritize understanding the mechanisms underlying these associations with a view to ultimately informing policies to reduce the injury burden in this population.