Using mobility status as a frailty indicator to improve the accuracy of a computerised five-level triage system among older patients in the emergency department

BACKGROUND: Owing to societal ageing, the number of older individuals visiting emergency departments (EDs) has increased in recent years. For this patient population, accurate triage systems are required. This retrospective cohort study assessed the accuracy of a computerised five-level triage system, the Taiwan Triage and Acuity System (TTAS), by determining its ability to predict in-hospital mortality in older adult patients and compare it with the corresponding rate in younger adult patients presenting to EDs. The association between frailty, which the current triage system does not consider, was also investigated. METHODS: The medical records of adult patients admitted to a single ED between 2016 and 2017 were reviewed. Data collected included information on demographics, triage level, frailty status, in-hospital mortality, and medical resource utilisation. The patients were divided into four age groups: two older adult groups (older: 65–84 years and very old: ≥85 years) and two younger adult groups (young: 18–39 and middle-aged: 40–64 years). RESULTS: Our study included 265,219 ED adult patients, of whom 64,104 and 16,009 were in the older and very old groups, respectively. The in-hospital mortality rate at each triage level increased with age. The ability of the TTAS to predict in-hospital mortality decreased with age (area under the receiver operating characteristic curve [AUROC]: young: 0.86; middle-aged, 0.84; and older and very old: 0.79). Frailty was associated with in-hospital mortality (odds ratio, 2.20; 95% confidence interval, 2.03–2.38). Adding mobility status as a frailty indicator to TTAS only slightly improved its ability to predict in-hospital mortality (AUROC: 0.74–0.77) in patients ≥65 years of age. CONCLUSIONS: The ability of the current triage system to predict in-hospital mortality decreases with age. Although frailty as mobility was associated with in-hospital mortality, its addition to the TTAS only slightly improved the accuracy with which in-hospital mortality in older patients presenting to EDs was predicted. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12873-022-00646-0.