Triage and Injury Severity Scores as predictors of mortality and hospital admission for injuries: A validation study

Abstract

Background Many emergency departments use a rating system to establish priority based on urgency: “triage”. The aim of this study was to evaluate the validity of triage in predicting hospitalization and mortality compared to that of the ICD-9-CM based Injury Severity Score (ISS). Methods Sources: The Emergency Information System 2000, the Hospital Information System 2000–2001 and the Mortality Register 2000–2001, of the Lazio Region. Case selection: Emergency department visits for traumas that occurred on the road or at home. Outcomes: Hospitalization and 30-day mortality. For each case, trauma diagnoses from the ICD-9-CM were given a corresponding ISS value. We performed logistic models, including age, sex and, alternatively, triage or ISS. We compared discrimination measures and calibration of the models. Results Out of 264,709 emergency department visits, 22,249 (8.4%) were followed by a hospitalization and 655 (0.2%) died within 30 days. ISS scores were calculated for 72,179 (27%) cases. Of the most urgent triage (840 patients), 78.3% (658) were hospitalized and 9% (76) died, while among patients with ISS ≥ 16 value (1276) 36.4% (464) of were hospitalized and 1.8% (23) died. Measures of discrimination and calibration showed similar results. The triage model had a better fitness in predicting hospitalization probability for home accidents (Hosmer–Lemeshow statistic: χ 2 triage = 5.5 vs χ 2 ISS = 34.3) and had a better performance for road accidents (ROC triage = 0.71 vs ROC ISS = 0.66). There were no differences between the models in predicting the probability of death. Conclusions The agreement between the two scales confirms the validity of triage as a clinical management tool in the emergency department, and as a proxy of trauma severity.