Accuracy of the qSOFA Score and RED Sign in Predicting Critical Care Requirements in Patients with Suspected Infection in the Emergency Department: A Retrospective Observational Study

Background and objectives: We aimed to compare the accuracy of positive quick sequential organ failure assessment (qSOFA) scores and the RED sign in predicting critical care requirements (CCRs) in patients with suspected infection who presented to the emergency department (ED). Materials and Methods: In this retrospective observational study, we examined adult patients with suspected infection in the ED from June 2018 to September 2018. A positive qSOFA (qSOFA+) was defined as the presence of ≥2 of the following criteria: altered mental status (AMS), systolic blood pressure (SBP) < 100 mmHg, and respiratory rate (RR) ≥ 22 breaths/min. A positive RED sign (RED sign+) was defined as the presence of at least one of the RED sign criteria: AMS, skin mottling, SBP < 90 mmHg, heart rate >130 beats/min, or RR > 30 breaths/min. A qSOFA/RED+ was defined as the presence of qSOFA+ or RED+. We applied these tools twice using the initial values upon ED arrival and all values within 2 h after ED arrival. The accuracy of qSOFA+, RED+, and qSOFA/RED+ in predicting CCR was assessed. Results: Data from 5353 patients with suspected infection were analyzed. The area under the receiver operating characteristic curve (AUC) of RED+ (0.67, 95% confidence interval [CI]: 0.65–0.70) and that of qSOFA/RED+ (0.68, 95% CI: 0.66–0.70, p < 0.01) were higher than the AUC of qSOFA+ (0.59, 95% CI: 0.57–0.60) in predicting CCR on ED arrival. The qSOFA/RED+ within 2 h showed the highest accuracy (AUC 0.72, 95% CI: 0.70–0.75, p < 0.001). Conclusions: The accuracy of the RED sign in predicting CCR in patients with suspected infection who presented at ED was better than that of qSOFA. The combined use of the RED sign and qSOFA (positive qSOFA or RED sign) showed the highest accuracy.