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

ObjectiveTo examine risks of severe adverse patient outcomes shortly after a left-without-being-seen emergency department (LWBS ED) visit since 2020.MethodsIn 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.ResultsDespite fewer monthly ED visits since 2020, temporal trends revealed sustained increases in monthly LWBS rates. LWBS ED visits after April 1, 2020 exceeded the baseline period's single-month LWBS maximum of 4.0% in 15 out of 36 months. The composite outcome of 7-day all-cause mortality or hospitalization was 3.4% in the recent period versus 2.9% in the baseline period (adjusted risk ratio [aRR] 1.14, 95% confidence interval [CI] 1.11-1.18) and remained elevated at 30 days (6.2% vs. 5.8%, respectively; aRR 1.05, 95% CI 1.03-1.07), despite similar rates of post-ED outpatient visits (7-day recent and baseline: 38.9% and 39.7%, respectively, p = 0.38; 30-day: 59.4% and 59.7%, respectively, p = 0.05).ConclusionsThe 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.