Predictors and in-hospital mortality associated with prolonged emergency department length of stay in New South Wales tertiary hospitals from 2017 to 2018.

Objective To determine specific patient, clinical and service factors associated with increased ED length of stay and investigate whether prolonged ED length of stay, as measured by emergency treatment performance (ETP) non-compliance, is an independent predictor of all cause 30-day mortality for patients presenting to, and admitted from ED. Methods This was a retrospective analysis of linked state-wide emergency, inpatient and death data from New South Wales. All patients who presented to a tertiary level public hospital (level 5 or 6) ED and admitted to an in-patient unit were included. Outcomes were the proportion of admitted patients who met ETP targets, and 30-day all-cause mortality. Results A total of 697 600 eligible cases were identified and analysed. The odds of meeting ETP benchmarks were 62% lower in those with complex or multiple medical comorbidities (odds ratio 0.38, 95% confidence interval 0.37-0.40, P < 0.001) compared with patients with no medical comorbidities. Admission under psychiatry, surgical and oncology service-related groups were associated with decreased ETP. The hazard ratio for 30-day all-cause mortality over time was 28% higher in those not meeting ETP benchmarks after adjusting for age, triage category, comorbidities, ICU and service-related group (hazard ratio 1.28, 95% confidence interval 1.26-1.30, P < 0.001). Conclusion Patients with complex and multiple medical comorbidities, and those admitted under certain service-related groups such as psychiatry, surgery and oncology were found to have poorer ETP performance. Overall, failure to meet ETP was associated with increased mortality after adjusting for age, case-mix, comorbidities and acuity.