Pulmonary fibrosis followed by severe pneumonia in patients with COVID-19 infection requiring mechanical ventilation: a prospective multicentre study

Backgrounds The management of lung complications, especially fibrosis, after COVID-19 pneumonia, is an important issue in the COVID-19 post-pandemic era. We aimed to investigate risk factors for pulmonary fibrosis development in patients with severe COVID-19 pneumonia.Methods Clinical and radiological data were prospectively collected from 64 patients who required mechanical ventilation due to COVID-19 pneumonia and were enrolled from eight hospitals in South Korea. Fibrotic changes on chest CT were evaluated by visual assessment, and extent of fibrosis (mixed disease score) was measured using automatic quantification system.Results 64 patients were enrolled, and their mean age was 58.2 years (64.1% were males). On chest CT (median interval: 60 days [IQR; 41–78 days] from enrolment), 35 (54.7%) patients showed ≥3 fibrotic lesions. The most frequent fibrotic change was traction bronchiectasis (47 patients, 73.4 %). Median extent of fibrosis measured by automatic quantification was 10.6% (IQR, 3.8–40.7%). In a multivariable Cox proportional hazard model, which included nine variables with a p value of