Objective: The Emergency Severity Index (ESI) is a new five-level triage instrument. The objective of this study was to determine whether there is an association between ESI triage status and short-term survival.
Methods: This was a survival analysis for a population-based, stratified random sample of patients over the age of 14 years who visited an urban, university-affiliated hospital emergency department (ED). Measures included ESI triage category (1 through 5), vital status obtained from the Social Security Administration, date of death (if applicable), and survival time in days. Data were analyzed with Kaplan-Meier survival analysis.
Results: Eighty-seven percent (202/232) of a random sample of patients appeared in the Social Security vital status registry. During the 252-day follow-up period, 19 patients (9%) died, 161 (80%) lived, and 22 (11%) had an unknown vital status. The ESI triage level was strongly associated with vital status at six months (Kaplan-Meier chi-square 25.9, p<0.0001). No patient in triage categories 4 and 5 died (lower limits of the 95% confidence interval for survival, 92% and 93%, respectively); whereas survival in triage category 1 was 68%, and in categories 2 and 3 it was 86% and 83%, respectively. Most of the deaths occurred within 60 days after the index ED visit. Sensitivity analyses biased against the instrument continued to demonstrate the association between triage status and survival.
Conclusions: The ESI triage status is associated with six-month survival. Patients with the highest three triage groups experienced decreased survival during the follow-up period, whereas all patients in the two lowest triage strata survived at least six months.