No added value of the modified NEWS score to predict clinical deterioration in COVID-19 patients

Dear Editor,

The current international outbreak of COVID-19 respiratory illness due to the SARS-CoV-2 virus results in high rates of hospitalisation and intensive care unit (ICU) admission [1]. ICU resources in Europe are limited [2], and managing ICU-bed flow is therefore vital to ensure high quality of care to all patients. The National Early Warning Score (NEWS) is recommended by the National Institute for Health and Care Excellence in its guidelines for predicting the risk of clinical deterioration of COVID-19 patients [3]. In this journal, Liao et al. [4] recently proposed a modified version of the NEWS score (mNEWS) for COVID-19 patients with age ≥ 65 years (score 3 points) added as an independent risk factor for survival. However, the authors did not provide data to support this modification and we did not identify published peer-reviewed research studies on it use to guide decision-making in COVID-19 patients. In this study, the performance of NEWS and mNEWS scores is examined to predict clinical deterioration and ICU admission in COVID-19 patients.

This retrospective study involved 363 adult patients with laboratory-confirmed infection of SARS-CoV-2 admitted to our institution, between March 10 and May 10, 2020. Using our institution database, NEWS and mNEWS values were collected throughout the ward admission. Clinical deterioration was defined as ICU admission or death. For statistical analysis, continuous measurements are presented as means ± SDs or as medians [IQRs], which compared with unpaired bilateral t-test or the Wilcoxon–Mann–Whitney test when appropriate. Categorical variables were expressed as numbers (%). Predictive performance of the NEWS and mNEWS scores was assessed using the area under the receiver operating characteristic (ROC_AUC) curve using the method described by DeLong et al. [5].

Over the study period, 416 adult COVID-19 patients were hospitalised and 53 patients with withholding or withdrawing life-support were excluded from the analysis. One hundred seventy-two patients presented a clinical deterioration (22 patients died and 150 were admitted to one of the 160 COVID-19 ICU beds) (Fig. 1 A). Median delay to ICU transfer was 1 day [0–3]. NEWS and mNEWS scores values were significantly higher in the group with a clinical deterioration (Fig. 1B). Median age was not significantly different between patients with a clinical deterioration (65 years [55–75]) or without (64 years [54–76]). The performance, as quantified by the ROC_AUC, was not significantly different between the NEWS and mNEWS scores to predict clinical deterioration (ROC_AUC 0.74 [CI95, 0.69–0.78] vs. 0.72 [CI95, 0.67–0.77]; P  = 0.274; Fig. 1  C) or ICU admission (ROC_AUC 0.73 [CI95, 0.68–0.78] vs. 0.70 [CI95, 0.65- 0.75]; P  = 0.088).

Fig. 1.

A. Cumulative number over the study period of patients with laboratory-confirmed infection of SARS-CoV-2 admitted in COVID-19 units (blue), transferred in COVID-19 ICUs (yellow) or died in hospital general wards (red); B. Box plot of the NEWS score (blue) and modified NEWS score (mNEWS; red) [4] values according the occurrence or not of a clinical deterioration in COVID-19 patients; C. Receiver operating characteristic (ROC) curves of NEWS (blue) and mNEWS (red) scores to predict clinical deterioration in COVID-19 patients.

The NEWS score was not accurate (ROC_AUC  < 0.75) to predict clinical deterioration in COVID-19 patients. This may be related to the specific respiratory failure outcome due to COVID-19. Moreover, the addition of the age as suggested by Liao et al. [4] in their modified version brings no added value in terms of performance.

Ethics approval and consent to participate

Patients and their relatives were informed of the possibility of the use of medical data for retrospective studies and did not manifest opposition. This study was approved by the local Ethics Commission (2020-53) and the French Society of Anaesthesia and Critical Care (00010254-2020-06).

Availability of data and material

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Funding

The authors receive no funding for this work.

Authors’ contributions

J.B., D.T. and P.S. contributed to the conception and design of the study, had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Y.B. and M.V. contributed to the acquisition of data. J.B., D.T. and P.S. contributed to the analysis and interpretation of the data. P.S. contributed to the statistical analyses. All authors participated in manuscript writing, revision and approval for final submission. Drs. Y.B and M.V contributed equally and shared first authorship.

Disclosure of interest

The authors declare that they have no competing interest.