The association between long emergency department stays and inpatient length of stay: a retrospective cohort study

Pressure on emergency departments (EDs) has increased, particularly since the COVID-19 pandemic. There has been limited research into the impact of prolonged emergency department length of stay on inpatient length of stay. This study aimed to evaluate whether a longer stay in the ED increases inpatient length of stay and to quantify any association. This was a single-centre, observational, retrospective cohort study of all ED patient episodes that led to inpatient admission from January 2022 to December 2022, at a tertiary hospital in the UK. Separate bivariate analyses were performed for adult and paediatric patients. The effect of multiple confounders for the adult population was evaluated with a logistic regression model. The outcome variable used was an inpatient stay of 7 days, as this is a recognised metric by National Health Service (NHS) England. From January 2022 to December 2022 there 31 131 admissions from the ED. 31 020 patient attendances were included, representing 23 286 individual patients. For an ED length of stay of less than 12 h, the inpatient length of stay median was 3 days (mean 7.87 days). This rose to 6 days for patients with an ED length of stay of 12 h or greater (mean 9.94 days). Even after adjusting for cofounding variables in adults, an ED length of stay of 12 h of more significantly increases the likelihood of a prolonged inpatient stay (OR 1.30, 95% Confidence Interval (CI) 1.23–1.37), and this effect increased for an ED length of stay of24 h or more (OR 1.50, 95% CI 1.38–1.63). In children, no statistically significant association was observed between ED length of stay and inpatient length of stay for a 12-hour threshold (Pearson Chi² test (9) = 9.4, p = 0.405). This study confirms that there is a significant association between a prolonged ED stay and an increased inpatient stay for patients remaining in the ED over 12 and 24 h.