Six-Month Follow-up Chest CT findings after Severe COVID-19 Pneumonia

BACKGROUND: Little is known about the long-term lung radiographic changes in convalescent COVID-19 patients, especially the severe cases. PURPOSE: To prospectively assess pulmonary sequelae and explore the risk factors for lung fibrotic-like changes on six-month follow-up chest CT of survivors of severe COVID-19 pneumonia. MATERIALS AND METHODS: 114 patients (80[70%] men; mean age, 54±12 years) were studied prospectively. Initial and follow-up CT scans were obtained on 17±11 days and 175±20 days respectively after symptom onset. Lung changes (opacification, consolidation, reticulation, and fibrotic-like changes) and CT extent scores (score per lobe, 0-5; maximum score, 25) were recorded. Patients were divided into two groups: group#1 presence and group#2 absence of CT evidence of fibrotic-like changes (traction bronchiectasis, parenchymal bands, and/or honeycombing) based on their six-month follow-up CT. Between-group differences were assessed by Fisher’s exact test, two-sample t-test or Mann-Whitney U test. Multiple logistic regression analyses were performed to identify the independent predictive factors of fibrotic-like changes. RESULTS: On follow-up CT, evidence of fibrotic-like changes was observed in 40/114 (35%) of patients (group#1), while the remaining 74/114 (65%) patients (group#2) showed either complete radiological resolution (43/114, 38%) or residual ground-glass opacification or interstitial thickening (31/114, 27%). Multivariable analysis identified age >50 years (odds ratio [OR]:8.5, 95%CI:1.9-38, p=.01), heart rate >100bpm at admission (OR:5.6, 95%CI:1.1-29, p=.04), duration of in-hospital stay ≥17 days (OR:5.5, 95%CI:1.5-21, p=.01), and acute respiratory distress syndrome (OR:13, 95%CI:3.3-55, p<.001), non-invasive mechanical ventilation (OR:6.3, 95%CI:1.3-30, p=.02) and total CT score ≥18 (OR:4.2, 95%CI:1.2-14, p=.02) on initial CT as independent predictors for lung fibrotic-like changes at 6 months. CONCLUSIONS: Six-month follow-up CT showed lung fibrotic-like changes in more than one-third of patients who survived severe COVID-19 pneumonia. These changes were associated with an older age, acute respiratory distress syndrome, longer in-hospital stays, tachycardia, non-invasive mechanical ventilation and higher initial chest CT score. See also the editorial by Wells, Devaraj, and Desai.