Superior performance of National Early Warning Score compared with quick Sepsis-related Organ Failure Assessment Score in predicting adverse outcomes: a retrospective observational study of patients in the prehospital setting

Background
Early intervention and response to deranged physiological parameters in the critically ill patient improve outcomes. A National Early Warning Score (NEWS) based on physiological observations has been developed for use throughout the National Health Service in the UK. The quick Sepsis-related Organ Failure Assessment Score (qSOFA) was developed as a simple bedside criterion to identify adult patients outwith the ICU with suspected infection who are likely to have a prolonged ICU stay or die in hospital. We aim to compare the ability of NEWS and qSOFA to predict adverse outcomes in a prehospital population.

Patients and methods
All clinical observations taken by emergency ambulance crews transporting patients to a single hospital were collated along with information relating to mortality over a 2-month period. The performance of the NEWS and qSOFA in identifying the endpoints of 30-day mortality, ICU admission and a combined endpoint of 48 h. ICU admission or 30-day mortality was analysed.

Results
Complete data were available for 1713 patients. For the primary outcome of ICU admission within 48 h or 30-day mortality, the odds ratio for a qSOFA score of 3 compared with 0 was 124.1 [95% confidence interval (CI): 13.5–1137.7] and the odds ratio for a high NEWS category, compared with the low NEWS category was 9.82 (95% CI: 5.74–16.81). Comparison of qSOFA and NEWS performance was assessed using receiver operating characteristic curves. The area under the receiver operating characteristic curve for the primary outcome for qSOFA was 0.679 (95% CI: 0.624–0.733), for NEWS category was 0.707 (95% CI: 0.654–0.761) and for NEWS total score was 0.740 (95% CI: 0.685–0.795). Comparison of the receiver operating characteristic curves between NEWS total score and qSOFA using DeLong’s test showed NEWS total score to be superior to qSOFA at predicting combined ICU admission within 48 h of presentation or 30-day mortality (P = 0.011).

Conclusion
Our study shows qSOFA can identify patients at risk of adverse outcomes in the prehospital setting. However, NEWS is superior to qSOFA in a prehospital environment at identifying patients at risk of adverse outcomes.