Pre-hospital National Early Warning Score (NEWS) is associated with in-hospital mortality and critical care unit admission: A cohort study.

•NEWS has a growing dominance in UK hospitals but is not widely used in ambulances.•NEWS calculated using ambulance observations is associated with in-hospital death and critical care unit admission.•NEWS could be used by ambulance crews as an objective tool to triage patients with acute illness.•A large scale trial should be carried out before widespread implementation of NEWS in ambulances.•It is unclear if NEWS could be used by a call-taker or bystander to triage a patient before the ambulance arrives.