Comparison of the Emergency Severity Index (ESI) and the Taiwan Triage System in predicting resource utilization

The importance of accurate triage in Taiwan is becoming more apparent with the increasing number of emergency department (ED) patients, and resources for the National Health Insurance becoming constrained. This study compared the ability of the Taiwan triage system (TTS) and the standardized 5-level Emergency Severity Index (ESI) triage system to predict ED resource utilization.

Patients arriving at the ED were triaged by both TTS and by using a two-page checklist of ESI criteria during the 3-month study period. The ESI triage level was calculated independently to avoid bias. Disease category (trauma vs. nontrauma), length of stay (LOS) and hospitalization data were evaluated.

A total of 3172 patients with both ESI and TWN evaluation were included. The distributions of ESI ratings within TTS level 1 were: ESI 1, 21.1%; ESI 2, 68.1%; ESI 3, 7.4%; ESI 4, 3.4%; ESI 5, 0%. For TTS level 3, they were: ESI 1, 0.1%; ESI 2, 26.2%; ESI 3, 39.5%; ESI 4, 27.5%; ESI 5, 6.8%. Hospitalization rates were 74.5%, 40.9% and 22.2% in TTS levels 1, 2 and 3, respectively; and were 96.2%, 47.0%, 30.9%, 6.7%and 6.6% in ESI levels 1, 2, 3, 4 and 5, respectively. TTS triaged more trauma patients as life-threatening/emergent condition than nontrauma patients (68.8% vs. 48.4%, p < 0.001). Triage by ESI, however, showed no significant difference in the percentage of trauma and nontrauma patients with highly acute conditions (44.2% vs. 46.6%, p = 0.230). Patients with ESI level 4 or 5 have significantly shorter ED LOS than those with ESI level 3.

ESI produces more accurate discriminating patient acuity, ED LOS and hospitalization rate than TTS. Adopting a standardized 5-level triage tool might improve resource utilization planning of ED practice.