Modification and Validation of a Complaint-Oriented Emergency Department Triage System: A Multicenter Observational Study

Purpose: The objective of this study was to modify and validate an emergency department (ED) triage system with improved prediction performance on hospital outcomes by modifying the Korean Triage and Acuity Scale (KTAS). Materials and Methods: We performed a retrospective observational study at three academic universities in South Korea. The KTAS code, determined by the chief complaint and the selected modifier of a patient, was used to derive the Modified KTAS (MKTAS). We calculated the area under the receiver operating characteristics curve (AUC) and the test characteristics to evaluate the performance of MKTAS to predict hospital mortality, critical outcome, and admission. Results: A total of 272402 and 128831 ED visits were used for the derivation and validation of MKTAS, respectively. Compared to KTAS, MKTAS had significantly higher AUC values for the prediction of hospital mortality [MKTAS 0.826 (0.818-0.835) vs. KTAS 0.794 (0.784-0.803)], critical outcome [MKTAS 0.836 (0.830-0.841) vs. 0.798 (0.792-0.804)], and admission [MKTAS 0.725 (0.723- 0.728) vs. KTAS 0.685 (0.682-0.688)]. The sensitivity for predicting hospital mortality and critical outcome, as well as the specificity for predicting admission, were significantly improved. Conclusion: MKTAS was derived by modifying the KTAS, and then validated. Compared with KTAS, MKTAS showed better discriminating ability to predict hospital outcomes. Continuous efforts to evaluate and modify widely used triage systems are required to improve their performance.