Turbulence in the system: Higher rates of left‐without‐being‐seen emergency department visits and associations with increased risks of adverse patient outcomes since 2020

Objective: To examine risks of severe adverse patient outcomes shortly after a left-without-being-seen emergency department (LWBS ED) visit since 2020. Methods: In this retrospective study using linked administrative data, we examined temporal trends in monthly rates of ED and LWBS visits for adults in Ontario, Canada, 2014‒2023. In patient-level analyses restricted to the first eligible LWBS ED visit, we used modified Poisson regression to compare the composite outcome of 7-day all-cause mortality or hospitalization following a LWBS ED visit for April 1, 2022‒March 31, 2023 (recent period) to April 1, 2014‒March 31, 2020 (baseline period), adjusted for age, sex, and Charlson comorbidity index. Conclusions: The rate of short-term mortality or hospitalization after a LWBS ED visit has recently increased, despite fewer ED visits/month and similar proportion of post-ED outpatient encounters. This concerning signal should prompt interventions to address system- and population-level causes.