First Visit Fallout: Canadian Triage and Acuity Scale (CTAS) and Emergency Department Returns

Introduction Unplanned return visits (URVs) to the emergency department (ED) within 72 hours are an important quality indicator in emergency medicine, linked to patient safety and the quality of initial care. This study examines whether the Canadian Triage and Acuity Scale (CTAS) category at the initial visit predicts the likelihood of hospital admission upon URV. Methods A retrospective analysis was conducted over a 12-month period at a tertiary care teaching hospital. URVs were defined as registrations within 72 hours of an initial ED discharge, excluding planned returns. Data were extracted from electronic health records, including demographics, CTAS category, disposition, and admission status. Statistical analyses included Pearson correlation, linear regression, and Fisher's exact test to examine relationships between CTAS and admission risk. Statistical significance was set at p < 0.05. Results Of 57,025 ED attendances, 82.1% (46,793) were discharged, of whom 7.6% (3,566) returned within 72 hours. Among URVs, 14.9% (532) resulted in admission. Admission rates on return varied by initial CTAS level, ranging from 23.1% (CTAS 1) to 4.8% (CTAS 5). CTAS 3 patients represented over half of all visits and the highest absolute number of return admissions. A strong negative correlation was observed between CTAS level and URV admission rate (Pearson r = -0.89; p = 0.04). Linear regression confirmed a statistically significant inverse trend, with each one-point increase in CTAS corresponding to a 5.4% absolute reduction in admission rate (R² = 0.90, p = 0.014). Patients triaged as CTAS 1-2 had a relative risk of 1.90 (95% CI: 1.57 to 2.30) for admission on return compared to those triaged as CTAS 3-5. Conclusions The initial CTAS level is a strong predictor of admission following URVs. Stratified analysis revealed that CTAS 3 patients comprise a clinically important group, both in volume and admission risk. These findings support the use of triage-based reporting in ED quality improvement initiatives.