Chest X-ray for predicting mortality and the need for ventilatory support in COVID-19 patients presenting to the emergency department

Balbi, Maurizio; Caroli, Anna; Corsi, Andrea; Milanese, Gianluca; Surace, Alessandra; Di Marco, Fabiano; Novelli, Luca; Silva, Mario; Lorini, Ferdinando Luca; Duca, Andrea; Cosentini, Roberto; Sverzellati, Nicola; Bonaffini, Pietro Andrea; Sironi, Sandro

OBJECTIVES: To evaluate the inter-rater agreement of chest X-ray (CXR) findings in coronavirus disease 2019 (COVID-19) and to determine the value of initial CXR along with demographic, clinical, and laboratory data at emergency department (ED) presentation for predicting mortality and the need for ventilatory support. METHODS: A total of 340 COVID-19 patients who underwent CXR in the ED setting (March 1–13, 2020) were retrospectively included. Two reviewers independently assessed CXR abnormalities, including ground-glass opacities (GGOs) and consolidation. Two scoring systems (Brixia score and percentage of lung involvement) were applied. Inter-rater agreement was assessed by weighted Cohen’s kappa (κ) or intraclass correlation coefficient (ICC). Predictors of death and respiratory support were identified by logistic or Poisson regression. RESULTS: GGO admixed with consolidation (n = 235, 69%) was the most common CXR finding. The inter-rater agreement was almost perfect for type of parenchymal opacity (κ = 0.90), Brixia score (ICC = 0.91), and percentage of lung involvement (ICC = 0.95). The Brixia score (OR: 1.19; 95% CI: 1.06, 1.34; p = 0.003), age (OR: 1.16; 95% CI: 1.11, 1.22; p < 0.001), PaO(2)/FiO(2) ratio (OR: 0.99; 95% CI: 0.98, 1; p = 0.002), and cardiovascular diseases (OR: 3.21; 95% CI: 1.28, 8.39; p = 0.014) predicted death. Percentage of lung involvement (OR: 1.02; 95% CI: 1.01, 1.03; p = 0.001) and PaO(2)/FiO(2) ratio (OR: 0.99; 95% CI: 0.99, 1.00; p < 0.001) were significant predictors of the need for ventilatory support. CONCLUSIONS: CXR is a reproducible tool for assessing COVID-19 and integrates with patient history, PaO(2)/FiO(2) ratio, and SpO(2) values to early predict mortality and the need for ventilatory support. KEY POINTS: • Chest X-ray is a reproducible tool for assessing COVID-19 pneumonia. • The Brixia score and percentage of lung involvement on chest X-ray integrate with patient history, PaO(2)/FIO(2) ratio, and SpO(2) values to early predict mortality and the need for ventilatory support in COVID-19 patients presenting to the emergency department. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00330-020-07270-1) contains supplementary material, which is available to authorized users.