External validation of the International Early Warning Score in non-traumatic emergency department patients: a prospective cohort
study

External validation of the International Early Warning Score in non-traumatic emergency department patients: a prospective cohort
study

Early warning score, International Early Warning Score, National Early Warning Score, Mortality prediction,
Intensive care admission, Emergency department

Background Emergency department (ED) overcrowding has become a global public health concern, underscoring
the importance of rapid and reliable risk stratification tools. Early warning scores are widely used to identify patients
at risk of deterioration and mortality. The recently developed International Early Warning Score (IEWS), which
incorporates age and sex adjustments into the National Early Warning Score (NEWS) model, has shown promising
results and has undergone initial external validation in a Danish cohort; however, no prospective external validation
has yet been conducted, and broader international validation remains limited. This study aimed to evaluate the
performance of IEWS compared with NEWS in predicting in-hospital mortality, 30-day mortality, and ICU admission
among adult ED patients.
Methods This prospective observational cohort study was conducted between July and August 2024 in a tertiary
university hospital ED with an annual census of ~70,000 visits. Adult patients presenting to the ED were included,
while trauma cases, patients without vital signs on arrival, interhospital transfers, and cases with incomplete data were
excluded. IEWS and NEWS were calculated at presentation. The primary outcome was all-cause in-hospital mortality;
secondary outcomes included 30-day mortality and ICU admission.
Results A total of 8,666 patients were analyzed. The median age was 40 years (IQR: 26–58), and 51.5% were female.
In-hospital mortality was 1.5% (n=134), and 30-day mortality was 1.9% (n=163). IEWS demonstrated excellent
discriminative ability for in-hospital and 30-day mortality (AUC: 0.944 and 0.930, respectively), and good performance
for ICU admission (AUC: 0.876). In contrast, NEWS showed good performance for in-hospital and 30-day mortality
(AUC: 0.884 and 0.848, respectively) and moderate performance for ICU admission (AUC: 0.781). IEWS consistently
outperformed NEWS across all outcomes (p<0.05, DeLong’s test).
Conclusion IEWS outperformed NEWS in predicting in-hospital mortality, 30-day mortality, and ICU admission
among non-traumatic ED patients. Given its high sensitivity, specificity, and overall discriminative performance, IEWS

Fatma Bayram1

, Buğra İlhan2*, Zeynep Kan3

, Oğuz Eroğlu2

and Turgut Deniz2

https://doi.org/10.1186/s12873-025-01440-4

2026

Peri Irawan

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