Association between cold weather and emergency department utilization among patients experiencing houselessness in a...

Lack of secure shelter is a contributing factor for healthcare utilization. Weather extremes, specifically extreme cold, is common in Canada. Because of the safety-net function of emergency departments (EDs), their use as shelters or warming centers is common in cold weather. Timely diversion resources may help mitigate ED crowding.

We conducted a cohort study using linked administrative data between April 2018 and March 2024 of all adult (> 17 years old) patients presenting to any EDs in the greater Edmonton area with an International Classification of Diseases, 10th revision diagnostic code with houselessness, unspecified. We obtained weather data from environment Canada for each day. The primary outcome was ED visits associated with houselessness based on mean daily temperature.

Between April 1st, 2018, and March 31st, 2024, there were 2,433,282 total ED visits recorded in the study area. There were 13,421 unique patients with ED visits associated with houselessness; more were male, and the median age was 39 (31, 49). The median visits per year were 5.2 (2.1, 12.4) for patients with a visit associated with houselessness compared to 1.2 (1.0, 3.3) for patients with stable housing. Proportion of ED visits associated with houselessness as a function of mean daily temperature revealed higher ED utilization with colder temperatures (< 0.0001). There was a 21% increase in expected ED visits associated with houselessness during periods of extreme cold.

Patients experiencing houselessness access EDs much more frequently than patients with stable housing. There was a much higher number of unique patients experiencing houselessness than expected. Utilization increases during times of extreme cold weather; and interventions to address these capacity issues are urgently needed.