Chest x-ray severity score in COVID-19 patients on emergency department admission: a two-centre study

Cristian Giuseppe Monaco,Gianmarco Della Pepa,Andrea Cozzi,Giovanni Di Leo,Laura Menicagli,Francesco Sardanelli,Federico Zaottini,Francesco Arpaia,Alessandro Villa,Ilan Rosenberg,Davide Astengo,Serena Carriero,Luca Alessandro Carbonaro,Simone Schiaffino

doi:10.1186/s41747-020-00195-w

Abstract

BackgroundIntegration of imaging and clinical parameters could improve the stratification of COVID-19 patients on emergency department (ED) admission. We aimed to assess the extent of COVID-19 pulmonary abnormalities on chest x-ray (CXR) using a semiquantitative severity score, correlating it with clinical data and testing its interobserver agreement.MethodsFrom February 22 to April 8, 2020, 926 consecutive patients referring to ED of two institutions in Northern Italy for suspected SARS-CoV-2 infection were reviewed. Patients with reverse transcriptase-polymerase chain reaction positive for SARS-CoV-2 and CXR images on ED admission were included (295 patients, median age 69 years, 199 males). Five readers independently and blindly reviewed all CXRs, rating pulmonary parenchymal involvement using a 0–3 semiquantitative score in 1-point increments on 6 lung zones (range 0–18). Interobserver agreement was assessed with weighted Cohen’s κ, correlations between median CXR score and clinical data with Spearman’s ρ, and the Mann-Whitney U test.ResultsMedian score showed negative correlation with SpO2 (ρ = -0.242, p < 0.001), positive correlation with white cell count (ρ = 0.277, p < 0.001), lactate dehydrogenase (ρ = 0.308, p < 0.001), and C-reactive protein (ρ = 0.367, p < 0.001), being significantly higher in subsequently dead patients (p = 0.003). Considering overall scores, readers’ pairings yielded moderate (κ = 0.449, p < 0.001) to almost perfect interobserver agreement (κ = 0.872, p < 0.001), with better interobserver agreement between readers of centre 2 (up to κ = 0.872, p < 0.001) than centre 1 (κ = 0.764, p < 0.001).ConclusionsProposed CXR pulmonary severity score in COVID-19 showed moderate to almost perfect interobserver agreement and significant but weak correlations with clinical parameters, potentially furthering CXR integration in patients’ stratification.

Highlights

Integration of imaging and clinical parameters could improve the stratification of COVID-19 patients on emergency department (ED) admission
Peripheral oxygen saturation (SpO2) largely determines the need of a COVID-19 patient to be transferred to intensive care units [1, 27]
There is a need to early stratify pulmonary involvement in COVID-19 patients: attaining this objective with chest x-ray (CXR) could add to the already established diagnostic relevance of this technique a role—shared with other clinical parameters commonly acquired on emergency department (ED) admission—in stratifying patients according to disease severity [17,18,19,20,21,22,23,24,25], potentially further curtailing the use of CT and the related workflow burden

Summary

Introduction

SpO2 largely determines the need of a COVID-19 patient to be transferred to intensive care units [1, 27]. In this view, there is a need to early stratify pulmonary involvement in COVID-19 patients: attaining this objective with CXR could add to the already established diagnostic relevance of this technique a role—shared with other clinical parameters commonly acquired on emergency department (ED) admission—in stratifying patients according to disease severity [17,18,19,20,21,22,23,24,25], potentially further curtailing the use of CT and the related workflow burden

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