Predictors of admission to hospital of patients triaged as nonurgent using the Canadian Triage and Acuity Scale

OBJECTIVES: To identify factors known prior to triage that might have predicted hospital admission for patients triaged by the Canadian Triage Acuity Scale (CTAS) as level 5 (CTAS 5, nonurgent) and to determine whether inappropriate triage occurred in the admitted CTAS 5 patients. METHODS: We reviewed the triage records of patients triaged as CTAS 5 at the emergency departments (EDs) of three tertiary care hospitals between April 2002 and September 2009. Two triage nurses unaware of the study objective independently assigned the CTAS level in 20% of randomly selected CTAS 5 patients who were admitted. We used the kappa statistic (κ) to measure the agreement among the raters in CTAS level between the assessment of the research nurses and the original triage assessment and regression analysis to identify independent predictors of admission to hospital. RESULTS: Of the 37,416 CTAS 5 patients included in this study, 587 (1.6%) were admitted. Agreement on CTAS assignment in CTAS 5 patients who were admitted was κ -0.9, (95% confidence interval [CI] -0.96 to -0.84). Age over 65 (odds ratio [OR] 5.46, 95% CI 4.57 to 6.53) and arrival by ambulance (OR 7.42, 95% CI 6.15 to 8.96) predicted hospital admission in CTAS 5 patients. CONCLUSIONS: Most of the CTAS 5 patients who were subsequently admitted to hospital may have qualified for a higher triage category. Two potential modifiers, age over 65 and arrival by ambulance, may have improved the prediction of admission in CTAS 5 patients. However, the consistent application of existing CTAS criteria may also be important to prevent incorrect triage.