Utility of the New Early Warning Score (NEWS) in combination with the neutrophil–lymphocyte ratio for the prediction of prognosis in older patients with pneumonia

OBJECTIVE: Predictors of prognosis are necessary for use in routine clinical practice for older patients with pneumonia, given the ageing of the population. Recently, the National Early Warning Score (NEWS), a comprehensive predictor of severity that consists solely of physiological indicators, has been proposed to predict the prognosis of pneumonia. The neutrophil/lymphocyte ratio (NLR) is a simple index of inflammation that may also be predictive of pneumonia. In the present study, we aimed to determine whether NEWS or a combination of NEWS and NLR predicts mortality in older patients with pneumonia. DESIGN: A retrospective cohort study. SETTING: A general hospital in Japan. PARTICIPANTS: We collected data from patients aged ≥65 years with pneumonia who were admitted between 2018 and 2020 (n=282; age=85.3 (7.9)). Data regarding vital signs, demographics and the length of hospital stay, in addition to the NEWS and NLR, were extracted from the participants’ electronic medical records. INTERVENTION: The utility of the combination of NEWS and NLR was assessed using NEWS×NLR and NEWS+NLR. MAIN OUTCOME MEASURES: Their predictive ability for 30-day mortality as the primary outcome was assessed using receiver operating characteristic (ROC) curve analysis. RESULTS: According to the NEWS classification, 80 (28.3%), 64 (22.7%) and 138 (48.9%) of the participants were at low, medium and high risk of mortality, respectively. The 30-day mortality for the entire cohort was 9.2% (n=26), and the mortality rate increased with the NEWS classification: low, 1.3%; medium, 7.8%; and high, 14.5%. The NLRs were 6.0 (4.2–9.8), 6.8 (4.8–10.4) and 14.6 (9.4–22.2), respectively (p<0.001). The areas under the ROC curves for 30-day mortality were 0.73 for the NEWS score, 0.84 for NEWS×NLR and 0.83 for NEWS+NLR, indicating that the combinations represent superior predictors of mortality to the NEWS alone. NEWS×NLR and NEWS+NLR tended to have better sensitivity, accuracy, positive predictive value and negative predictive value than NEWS alone (p=0.06). CONCLUSIONS: A combination of the NEWS and NLR (NEWS×NLR or NEWS+NLR) may be superior to the NEWS alone for the prediction of 30-day mortality in older patients with pneumonia. However, further validation of these combinations for use in the prediction of prognosis is required.