Validity of the Japan Acuity and Triage Scale in elderly patients: A cohort study

In developed nations, the age of patients in emergency departments (ED) continues to increase. Many emergency triage systems, such as the Canadian Triage and Acuity Scale (CTAS), triage patients as a homogenous group, regardless of age. However, older adults have multiple comorbidities and a higher risk of undertriage. The Japan Acuity and Triage Scale (JTAS) was developed based on the CTAS and has been validated for overall adults. We assessed the validity of the JTAS for use in elderly ED patients.

This was a secondary analysis of a cohort study that previously validated the JTAS in self-presenting adults of all ages in the ED of a Japanese tertiary-care hospital. We included non-transferred patients who were ≥65 years old and triaged between June 2013 and May 2014. Our primary outcome measures were overall admission and ED length of stay. Our secondary outcomes included admission to the intensive care units (ICUs) and in-hospital mortality. We examined the association between the triage level and patient outcomes with multivariable logistic regression analysis (overall and ICU admission and in-hospital mortality) and the Kruskal-Wallis rank-sum test (ED length of stay).

We included a total of 11,087 elderly patients in our study. Higher odds ratios for overall and ICU admission and in-hospital mortality corresponded to higher acuity levels. ED length of stay was significantly longer in patients with a higher JTAS level (p < 0.001). Twenty-nine percent of admissions who were triaged as lower acuity levels were related to non-acute diseases including malignancy-related events.

Our study suggests an association between the JTAS triage level and clinical outcomes in self-presenting elderly patients, thereby demonstrating the validity of the JTAS in these patients. However, admission due to chronic diseases including malignancy was common in patients who were rated as low acuity level.