Predicting admission and mortality with the Emergency Severity Index and the Manchester Triage System: a retrospective observational study

Objective: To compare the degree to which the Emergency Severity Index (ESI) and the Manchester Triage System (MTS) predict admission and mortality. Methods: A retrospective observational study of four emergency department (ED) databases was conducted. Patients who presented to the ED between 1 January and 18 July 2006 and were triaged with the ESI or MTS were included in the study. Results: 37 974 patients triaged with the ESI and 34 258 patients triaged with the MTS were included. The likelihood of admission decreased significantly with urgency categories in both populations, and was greater for patients triaged with the ESI than with the MTS. Mortality rates were low in both populations. Most patients who died were triaged in the most urgent triage categories of both systems. Conclusion: Both the ESI and MTS predicted admission well. The ESI was a better predictor of admission than the MTS. Mortality is associated with urgency categories of both triage systems.