Chest X-ray Severity and its Association with Outcomes in Patients with COVID-19 Presenting to the Emergency Department

ABSTRACT

BackgroundSeverity of radiographic abnormalities on chest X-ray (CXR) in patients with COVID-19 has been shown to be associated with worse outcomes, but studies are limited by different scoring systems, sample size, patient age and study duration. Data regarding the longitudinal evolution of radiographic abnormalities and its association with outcomes is scarce. We sought to evaluate these questions using a well-validated scoring system (the Radiographic Assessment of Lung Edema [RALE] score) using data over 6 months from a large, multi-hospital healthcare system. MethodsWe collected clinical and demographic data and quantified radiographic edema on CXRs obtained in the emergency department (ED) as well as on days 1-2 and 3-5 (in those admitted) in patients with a nasopharyngeal swab positive for SARS-CoV-2 PCR visiting the ED for COVID-19-related complaints between March and September 2020. We examined the association of baseline and longitudinal evolution of radiographic edema with severity of hypoxemia and clinical outcomes. Results870 patients were included (median age 53.6, 50.8% female). Inter-rate agreement for RALE scores was excellent (ICC = 0.84, 95% CI 0.82 - 0.87, p < 0.0001). RALE scores correlated with hypoxemia as quantified by SpO2-FiO2 ratio (r = -0.42, p < 0.001). Admitted patients had higher RALE scores than those discharged (6 [2, 11] vs 0 [0, 3], p < 0.001). An increase of RALE score of 4 or more was associated with worse 30-day survival (p < 0.01). Larger increases in the RALE score were associated with worse survival. ConclusionsThe RALE score is reproducible and easily implementable in adult patients presenting to the ED with COVID-19. Its association with physiologic parameters and outcomes at baseline and longitudinally makes it a readily available tool for prognostication and early ICU triage, particularly in patients with worsening radiographic edema.