The ROX index has greater predictive validity than NEWS2 for deterioration in Covid-19.

BACKGROUND: Patients admitted to hospital with Covid-19 are at risk of deterioration. The National Early Warning Score (NEWS2) is widely recommended, however it's validity in Covid-19 is not established and indices more specific for respiratory failure may be more appropriate. We aim to describe the physiological antecedents to deterioration, test the predictive validity of NEWS2 and compare this to the ROX index ([SpO2/FiO2]/respiratory rate). METHOD: A single centre retrospective cohort study of adult patients who were admitted to a medical ward, between 1/3/20 and 30/5/20, with positive results for SARS-CoV-2 RNA. Physiological observations and the NEWS2 were extracted and analysed. The primary outcome was a composite of cardiac arrest, unplanned critical care admission or death within 24 hours. A generalized linear model was used to assess the association of physiological values, NEWS2 and ROX with the outcome. FINDINGS: The primary outcome occurred in 186 patients (26%). In the preceding 24 hours, deterioration was most marked in respiratory parameters, specifically in escalating oxygen requirement; tachypnoea was a late sign, whilst cardiovascular observations remained stable. The area under the receiver operating curve was 0.815 (95% CI 0.804-0.826) for NEWS2 and 0.848 (95% CI 0.837-0.858) for ROX. Applying the optimal level of ROX, the majority of patients triggered four hours earlier than with NEWS2 of 5. INTERPRETATION: NEWS2 may under-perform in Covid-19 due to intrinsic limitations of the design and the unique pathophysiology of the disease. A simple index utilising respiratory parameters can outperform NEWS2 in predicting the occurrence of adverse events.

The performance of the National Early Warning Score and National Early Warning Score 2 in hospitalised patients infected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

INTRODUCTION: Since the introduction of the UK's National Early Warning Score (NEWS) and its modification, NEWS2, coronavirus disease 2019 (COVID-19), has caused a worldwide pandemic. NEWS and NEWS2 have good predictive abilities in patients with other infections and sepsis, however there is little evidence of their performance in COVID-19. METHODS: Using receiver-operating characteristics analyses, we used the area under the receiver operating characteristic (AUROC) curve to evaluate the performance of NEWS or NEWS2 to discriminate the combined outcome of either death or intensive care unit (ICU) admission within 24 h of a vital sign set in five cohorts (COVID-19 POSITIVE, n = 405; COVID-19 NOT DETECTED, n = 1716; COVID-19 NOT TESTED, n = 2686; CONTROL 2018, n = 6273; CONTROL 2019, n = 6523). RESULTS: The AUROC values for NEWS or NEWS2 for the combined outcome were: COVID-19 POSITIVE, 0.882 (0.868-0.895); COVID-19 NOT DETECTED, 0.875 (0.861-0.89); COVID-19 NOT TESTED, 0.876 (0.85-0.902); CONTROL 2018, 0.894 (0.884-0.904); CONTROL 2019, 0.842 (0.829-0.855). CONCLUSIONS: The finding that NEWS or NEWS2 performance was good and similar in all five cohorts (range = 0.842-0.894) suggests that amendments to NEWS or NEWS2, such as the addition of new covariates or the need to change the weighting of existing parameters, are unnecessary when evaluating patients with COVID-19. Our results support the national and international recommendations for the use of NEWS or NEWS2 for the assessment of acute-illness severity in patients with COVID-19.