Prediction of emergent heart failure death by semi-quantitative triage risk stratification

Objectives — Generic triage risk assessments are widely used in the emergency department (ED) but have not been validated for prediction of short-term risk among patients with acute heart failure (HF). The objective was to evaluate the Canadian Triage Acuity Scale (CTAS) for prediction of early death among HF patients.

Methods — Included patients presenting with HF to an ED in Ontario from April 2003 to March 2007. Used the National Ambulatory Care Reporting System and vital statistics databases to examine care and outcomes.

Results — Among 68,380 patients (76±12 years, 49.4% men), early mortality was stratified with death rates of 9.9%, 1.9%, 0.9%, and 0.5% at 1-day, and 17.2%, 5.9%, 3.8%, and 2.5% at 7-days, for CTAS 1, 2, 3, and 4-5, respectively. Compared to lower acuity (CTAS 4–5) patients, adjusted odds ratios (aOR) for 1-day death were 1.32 (95% CI; 0.93–1.88; p=0.12) for CTAS 3, 2.41 (95%CI; 1.71–3.40; p<0.001) for CTAS 2, and highest for CTAS 1: 9.06 (95% CI; 6.28-13.06; p<0.001). Predictors of triage-critical (CTAS 1) status included oxygen saturation <90% (aOR 5.92, 95%CI; 3.09–11.81; p<0.001), respiratory rate >24 breaths/minute (aOR 1.96, 95% CI; 1.05–3.67; p=0.034), and arrival by paramedic (aOR 3.52, 95% CI; 1.70–8.02; p=0.001). While age/sex-adjusted CTAS score provided good discrimination for ED (c-statistic = 0.817) and 1-day (c-statistic=0.724) death, mortality prediction was improved further after accounting for cardiac and non-cardiac co-morbidities (c-statistics 0.882 and 0.810, respectively; both p<0.001).

Conclusions — A semi-quantitative triage acuity scale assigned at ED presentation and based largely on respiratory factors predicted emergent death among HF patients.