The relationship between prolonged emergency department (ED) wait times and short-term all-cause mortality: an analysis of multi-institutional administrative data in Alberta.

Objective: ED wait times have been linked to adverse patient outcomes, including increased mortality. We sought to assess the consequences of ED wait times on patient outcomes.

Methods: We conducted a cohort study using administrative data from the 14 Alberta highest-volume adult EDs (2017-2022). The relationships between different components of ED wait times and patient short-term all-cause mortality (primary outcome:7-day mortality, and secondary outcome: 30-day mortality) were assessed using Multi-level logistic regression with adjustment for age, gender, the Canadian Triage and Acuity Scale (CTAS), Deprivation Index, Charlson Comorbidity Index, disposition status, hospital EDs, and visit date.

Results: Among 1,358,935 unique adult patient ED visits, 22,692 (1.7%) deaths occurred within 7 days, and 47,441 (3.5%) occurred within 30 days after leaving the EDs. Among the entire cohort, there were no associations between prolonged total length of stay, boarding time or time from arrival to physician initial assessment, and an increased risk of the primary outcome. However, in subgroup analyses, among discharged patients, total length of stay of more than 6 hours was associated with an increased risk of 7-day mortality, and demonstrated a dose-response association with an increased risk of 30-day mortality [odds ratio (OR), 95% confidence interval (CI), (reference<6 hrs.): 1.3 (1.2-1.5) at 6-10 h, 1.8 (1.6-2.0), at 10-19 h, and 2.2 (1.8-2.7) at ≥ 19 h].

Conclusions: We did not observe an association between ED wait times and 7-day mortality across the overall patient population. Future work should identify specific patient groups that may be at risk of harm from ED wait times to tailor ED crowding and risk mitigation strategies to reduce adverse outcomes among the most at-risk patients.