The Impact of Pain on Triage Accuracy, Hospital Admission, and Length of Stay in Patients Presenting to the Emergency Department: A Systematic Review.

Introduction: Acute pain serves as a modifier in five-level triage systems, such as the Canadian Triage and Acuity Scale (CTAS) and the Korean Triage and Acuity Scale (KTAS). This systematic review aimed to synthesize existing evidence on the impact of pain on triage accuracy, hospital admission, and length of stay in patients presenting to the emergency department (ED). Methods: A systematic search was conducted in PubMed and Google Scholar for English studies published between 2000 and 2026. Studies that reported associations between pain score, triage accuracy, hospital admission, and length of stay in patients presenting to the ED were included. Data extraction and quality assessment were performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: Out of 484 initial records, independent screening yielded 6 original cohort studies for final inclusion. The studies encompassed a total of 247,624 patients, with moderate to high methodological quality in the qualitative synthesis. Self-reported pain scores demonstrated no predictive relationship with admission rates or ED length of stay. However, their mandatory integration into triage protocols resulted in over-triage and reduced system accuracy. Based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, the overall certainty of evidence was determined to be moderate. Conclusion: Self-reported pain lacks independent predictive value for hospital admission or ED length of stay, and its mandatory integration into triage systems leads to over-triage. Rather than determining acuity priority, pain assessment should be decoupled from the primary triage decision and be linked to dedicated pain-management protocols instead.