Evolution of radiologic alterations in patients unvaccinated with COVID-19 pneumonia and prediction of lung fibrosis development at 6 months according to predictive model.

INTRODUCTION: Alteration in pulmonary function tests and radiological abnormalities are present in a significant percentage of COVID-19 survivors. Our aim is to evaluate radiological findings and functional respiratory parameters involved in lung fibrosis at six months after SARS-CoV-2 pneumonia and use initial score of the predictive model to predict fibrotic-like changes at 6 months.

MATERIAL AND METHODS: Prospective observational study including unvaccinated patients with COVID-19 pneumonia. Pulmonary function tests and chest CT were performed six months after acute pneumonia.

RESULTS: 109 patients were included. Bilateral ground-glass opacities (94%) were the most frequent radiological finding, followed by bilateral consolidations (36%) and crazy paving patterns (28%). Ct tracking shows a significant decrease in bilateral ground glass, consolidations and bilateral crazy paving at 6 months. In contrast, architectural distortion tends to increase over time. The presence of bronchial dilatation, subpleural curved line and parenchymal bands on initial CT were associated with radiological signs of lung fibrosis at 6 months. An initial score of the predictive model >0.6 predicts fibrotic-like changes at 6 months (AUC 77.8%; Specificity 85.4%; Sensitivity 58.1%). The proportion of patients with DLCO <80% was 55%.

CONCLUSIONS: In 50 patients, 6 months CT detected signs of fibrotic-like changes. The presence of bronchial dilatation, subpleural curved line and parenchymal bands could be used as early predictors of fibrotic-like changes in patients with COVID-19 pneumonia. Initial score of the predictive model >0,6 allows the selection of patients at risk of developing pulmonary fibrotic-like changes. DLCO was the one most frequently impaired at 6 months.