AUTHOR=Cocconcelli Elisabetta , Bernardinello Nicol , Giraudo Chiara , Castelli Gioele , Giorgino Adelaide , Leoni Davide , Petrarulo Simone , Ferrari Anna , Saetta Marina , Cattelan Annamaria , Spagnolo Paolo , Balestro Elisabetta 

TITLE=Characteristics and Prognostic Factors of Pulmonary Fibrosis After COVID-19 Pneumonia

JOURNAL=Frontiers in Medicine

VOLUME=Volume 8 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.823600

DOI=10.3389/fmed.2021.823600

ISSN=2296-858X

ABSTRACT=Background. Little is known about the long-term pulmonary sequelae after COVID-19 infection. 
Hence, the aim of this study is to characterize patients with persisting pulmonary sequelae at follow-up after hospitalization. We also aimed to explore clinical and radiological predictors of pulmonary fibrosis following COVID-19. 
Methods. Two hundred-twenty consecutive patients were evaluated at 3–6 months after discharge with high-resolution computed tomography (HRCT) and categorized as recovered (REC) or not recovered (NOT-REC). Both HRCTs at hospitalization (HRCT0), when available, and HRCT1 during follow-up were analyzed semi-quantitatively as: ground glass opacities (Alveolar Score,AS), consolidations (CONS) and reticulations (Interstitial Score, IS). 
Results. 175/220 (80%) patients showed disease resolution at their initial radiological evaluation following discharge. NOT-REC patients (45/220; 20%) were mostly older males [66 (35-85) years vs. 56 (19 - 87); p=0.03] with a longer in-hospital stay [16 (0 - 75) vs. 8 (1 - 52) days; p<0.0001], and lower P/F at admission [233 (40-424) vs. 318 (33-543); p=0.04]. Moreover, NOT-REC patients presented, at hospital admission, higher ALV [14(0.0–62.0) vs. 4.4(0.0–44.0);p=0.0005], CONS [1.9(0.0–26.0 vs. 0.4(0.0–18.0);p=0.0064], and IS [11.5(0.0– 29.0) vs. 0.0(0.0–22.0);p<0.0001] compared to REC patients. On multivariate analysis, the presence of CONS and IS at HRCT0 were independent predictors of radiological sequelae at follow-up [OR 14.87(95%CI: 1.25–175.8; p=0.03) and 28.9 (95%CI: 2.17–386.6; p=0.01, respectively). 
Conclusions. In our population, only twenty percent of patients showed persistent lung abnormalities at six-months after hospitalization for COVID-19 pneumonia. These patients are predominantly older males with longer hospital stay. The presence of reticulations and consolidation on HRCT at hospital admission predict the persistence of radiological abnormalities during follow-up.