Longitudinal Assessment of Chest Computed Tomographic Findings After COVID-19 Infection

Background: The long-term evolution of fibrotic-like changes following moderate-to-severe COVID-19 pneumonia remains unclear. This study aimed to characterize the temporal progression of these abnormalities over a 12-month period. Methods: This study was conducted as an ancillary analysis of a previously reported multicenter prospective observational study. From September 2020 to September 2021, we enrolled hospitalized adults (≥20 years old) with polymerase chain reaction- or antigen-confirmed COVID-19 classified as moderate or severe. A total of 83 patients who underwent chest CT at both admission and 12 months were included. All CT scans were independently reviewed by two board-certified radiologists. Fibrotic-like changes and CT severity scores (CTSS) were assessed at admission and at 3-, 6-, 9-, and 12-month follow-up. Clinical variables associated with fibrotic-like changes were analyzed. Results: Fibrotic-like changes were present in 18/83 (21.7%) patients at admission and increased to 39/83 (47.0%) patients at 12 months. Their presence at admission was associated with older age, whereas their presence at 12 months was associated with older age and longer length of hospital stay. The prevalence of fibrotic-like changes increased significantly within the first three months (p<0.001) and remained stable thereafter. CTSS also increased significantly during the first three months (p=0.01), without further progression. Conclusion: Fibrotic-like lung changes after COVID-19 pneumonia tend to progress mainly during the early post-hospitalization phase and stabilize by three months, with no substantial subsequent deterioration.