6 Prognostic Value of qSOFA, SIRS and News in the Emergency Department for Predicting 7-Day Mortality: A Prospective Study

Abstract

Sepsis is the primary cause of death from infection worldwide. In 2016, Sepsis-3, a new clinical concept termed “quick Sepsis-Related Organ Failure Assessment” (qSOFA) was introduced to identify high-risk patients with suspected infection (outside of critical care settings). The present study aimed to validate qSOFA for use in a university hospital emergency department in Hong Kong. Furthermore, we compared the prognostic value of qSOFA and the previous Systemic Inflammatory Response Syndrome (SIRS) criteria, along with a widely used early warning score, the National Early Warning Score (NEWS). This single-center prospective study was conducted in the ED of Prince of Wales Hospital in Hong Kong between July 2016 and June 2017. 1253 non-trauma general ED patients and triaged as category 2 (Emergency) and 3 (Urgent) were recruited. All variables for calculating qSOFA, SIRS and NEWS were collected. The outcome measure was 7-day mortality. Venous lactate was also measured to investigate whether lactate levels were incremental for the prediction of 7-day mortality. The prognostic value of qSOFA, SIRS and NEWS to predict 7-day mortality was studied. Receiver operating characteristic analyses were performed to determine the area under the curve (AUC), sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios for qSOFA≥2, SIRS≥2 and NEWS≥5. We recruited 1253 patients of median age 72 years (IQR: 59-84); 638 (50.9%) were male. Overall 7-day mortality in this cohort of general ED patients was 2.6%. The prognostic value for prediction of 7-day mortality, with AUCs for qSOFA≥2, SIRS≥2 and NEWS≥5 were 0.57 (95% CI 0.54-0.60), 0.70 (95% CI 0.67-0.72) and 0.68 (95% CI 0.66-0.71) respectively. Using pairwise comparison of ROC curves, the AUC of NEWS≥5 (p=0.0144) and SIRS≥2 (p=0.0116) were better than qSOFA≥2 to predict 7-day mortality in ED patients. The AUC of lactate ≥2mmol/L to predict 7-day mortality was 0.63 (95% CI 0.61-0.66). The combination of lactate level ≥2mmol/L with qSOFA≥2, SIRS≥2 and NEWS≥5, AUC were 0.56 (95% CI 0.53-0.59), 0.65 (95% CI 0.62-0.67) and 0.63 (95% CI 0.60-0.66) respectively. In addition, the positive likelihood ratios of qSOFA≥2, SIRS≥2 and NEWS≥5 to predict 7-day mortality were 14.17 (95% CI 5.37-37.38), 2.44 (95% CI 2.04-3.75) and 3.70 (95% CI 2.54-5.39). Among emergency and urgent patients presenting to the ED, NEWS and SIRS have greater prognostic value for 7-day mortality compared to qSOFA. Combinations of lactate level with qSOFA, SIRS or NEWS did not improve their prognostic value in predicting 7-day mortality in ED patients.