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

Abstract

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.