Removing systolic blood pressure from the National Early Warning Score (NEWS) for mortality prediction: an observational study.

Abstract

Background: Vital signs in triage are essential for effective risk stratification in the emergency department (ED). They are also increasingly used to calculate an early warning score at the time of presentation. However, obtaining a blood pressure is more time-consuming than other vital signs, potentially delaying care for subsequent patients. Additionally, studies indicate that this measure is not always collected. This study aimed to evaluate whether removing systolic blood pressure (SBP) from the National Early Warning Score (NEWS) affects the prediction of mortality.

Methods: This prospective observational single-centre study included all patients presenting to triage of the General Hospital of Merano, Italy, from 1 June 2022 to 30 June 2023. Vital signs were recorded for each patient. NEWS and NEWS without SBP (NEWS-SBP) were computed. The ability of the two versions of the score to predict mortality at 48 hours, 7 days and 30 days was evaluated using the Area Under the Receiver Operating Characteristic curves (AUROC).

Results: Data were recorded from 26 249 patients. For predicting 7-day and 30-day mortality, NEWS had a significantly higher AUROC than NEWS-SBP (7-day mortality: 0.84, 95% CI: 0.81 to 0.87 vs 0.83, 95% CI: 0.80 to 0.86; p=0.012, and 30-day mortality: 0.79, 95% CI: 0.77 to 0.81 vs 0.77, 95% CI: 0.75 to 0.79; p<0.001). No significant difference was found in the AUROC for the prediction of 48-hour mortality (NEWS: 0.89, 95% CI: 0.85 to 0.92 vs NEWS-SBP 0.88, 95% CI: 0.85 to 0.91; p=0.139).

Conclusion: The NEWS-SBP was equivalent to the complete score for prediction of 48-hour mortality, but was less accurate in predicting medium and long-term mortality among ED patients. Further research is needed to clarify potential advantages in reducing triage time and whether these benefits outweigh the loss of prognostic accuracy.