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

BACKGROUND: Few 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 and 20 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 (HRCT(0)), when available, and HRCT(1) during follow-up were analyzed semiquantitatively as follows: ground-glass opacities (alveolar score, AS), consolidations (CONS), and reticulations (interstitial score, IS). RESULTS: A total of 175/220 (80%) patients showed disease resolution at their initial radiological evaluation following discharge. NOT-REC patients (45/220; 20%) were mostly older men [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 HRCT(0) was 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 6 months after hospitalization for COVID-19 pneumonia. These patients are predominantly older men with longer hospital stay. The presence of reticulations and consolidation on HRCT at hospital admission predicts the persistence of radiological abnormalities during follow-up.