Association Between Time Spent in the Emergency Department and 30-Day Mortality: A Population-Level Observational...

In this study, we investigated the association between time spent in Type 1 emergency departments (EDs) (consultant led 24-hour service with full resuscitation facilities) and all-cause mortality 30 days after leaving the department alive (either discharged home or admitted to inpatient care).

This was a cross-sectional, retrospective, observational study using national linked data. We included individuals who visited a Type 1 ED between 21^st March 2021 and 31^st March 2022, under a nonimmediate acuity who survived to discharge or admission to inpatient care. Fitting a logistic regression model, we assessed the association between time spent in the ED and the risk of all-cause, 30-day death following departure.

Of 6,721,179 individuals (mean age 41.3 years; 52.6% women, 81.4% White), 1.3% died within 30 days of visit. After controlling for confounders, compared with patients who spent 2 hours in the ED, the adjusted odds of postdischarge death were: 1.1 times higher (1.07 to 1.14) for 3 hours; 1.6 times (1.48 to 1.68) for 6 hours; 1.9 times (1.80 to 2.03) for 9 hours; and 2.1 times (2.02 to 2.28) for 12 hours.

Longer time spent in the ED for nonimmediate care is associated with increased risk of all-cause mortality within 30 days of discharge or admission. However, the reasons for this association are uncertain and may reflect residual confounding, rather than a direct causal effect of time spent in the ED. Therefore, further research is needed to understand causal drivers of postdischarge mortality.