Predictive Value of NEWS2 Score
The NEWS2 score is a highly effective predictor of mortality and clinical deterioration, with excellent accuracy for identifying patients at risk of severe illness or death, particularly in sepsis and emergency department settings. 1
Risk Stratification Performance
NEWS2 consistently outperforms other sepsis screening tools in detecting patients at risk of severe illness or death from sepsis, and NICE recommends it as the standard tool for risk stratification in acute hospital, mental health, and ambulance settings. 2
Mortality Prediction
NEWS2 demonstrates excellent predictive accuracy for mortality with area under the receiver operating characteristic curve (AUROC) values of 0.963 for 2-day mortality, 0.946 for 7-day mortality, and 0.915 for 30-day mortality in emergency department patients. 3
Each point increase in NEWS2 score significantly increases mortality risk: OR 1.75 at 2 days, OR 1.69 at 7 days, and OR 1.58 at 30 days. 3
In a prospective study, survivors had a mean NEWS2 score of 4.36 ± 2.698, while non-survivors had a significantly higher mean score of 13.14 ± 1.406, demonstrating strong correlation between higher scores and mortality. 4
Clinical Deterioration Detection
NEWS2 ≥ 5 identifies clinical deterioration with high sensitivity (0.98) but moderate specificity (0.28), resulting in a negative predictive value of 0.96 for serious events including respiratory support initiation, ICU admission, or death. 5
The optimal trigger point for escalation is NEWS2 ≥ 4, which provides the best balance of sensitivity and specificity for predicting adverse outcomes in emergency department patients. 3
A score of 3 in any single parameter indicates increased risk regardless of total score, based on Royal College of Physicians recommendations. 1
Risk Categories and Clinical Significance
NEWS2 stratifies risk into four validated categories that directly correlate with ICU admission and mortality risk: 1, 2
- High risk (≥7): Suggests high risk of severe illness or death from sepsis
- Moderate risk (5-6): Suggests moderate risk of severe illness or death
- Low risk (1-4): Suggests low risk of severe illness or death
- Very low risk (0): Suggests very low risk of severe illness or death
In patients with NEWS2 >5, the risks of ICU admission and mortality increase substantially. 1
Comparative Performance
NEWS2's negative predictive value (0.96) significantly exceeds that of Modified Early Warning Score (MEWS) (0.59) and quick Sepsis Related Organ Failure Assessment (qSOFA) (0.58) for identifying clinical deterioration. 5
For postoperative brain tumor patients, NEWS2 demonstrated strong performance (AUROC 0.860) for predicting unplanned ICU admissions within 72 hours. 6
Important Caveats and Limitations
Always interpret NEWS2 scores in the context of underlying physiology and comorbidities, as the score may underestimate risk in certain populations. 1
Consider the patient's risk higher than the NEWS2 suggests if their condition is deteriorating or has not improved since any previous score calculation or intervention. 1
Clinical signs that override NEWS2 scoring include mottled or ashen appearance, non-blanching petechial or purpuric rash, or cyanosis of skin, lips, or tongue—these warrant immediate high-risk classification regardless of score. 1
In rapid response team settings, NEWS2 showed only acceptable accuracy for mortality prediction (AUROC 0.67) and relatively weak performance for composite outcomes (AUROC 0.62), suggesting NEWS2 alone may be insufficient for risk stratification in already-deteriorating patients. 7
The high sensitivity comes at the expense of a relatively high false-trigger rate (specificity 0.28), which may lead to resource utilization concerns but ensures few deteriorating patients are missed. 5
Clinical Application Algorithm
Use NEWS2 for continuous monitoring with frequency based on risk level: 1
- High risk (≥7): Re-calculate every 30 minutes
- Moderate risk (5-6): Re-calculate every hour
- Low risk (1-4): Re-calculate every 4-6 hours
- Very low risk (0): Follow standard protocol
Do not delay reassessment if clinical condition deteriorates despite an initially low score, as dynamic changes are more important than static values. 2