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

Abstract

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 <0.10 in an unadjusted analysis as well as age, sex and Body Mass Index, male sex (HR, 3.01; 95% CI, 1.27 to 7.11) and higher initial Sequential Organ Failure Assessment (SOFA) score (HR, 1.18; 95% CI, 1.02 to 1.37) were independently associated with pulmonary fibrosis (≥3 fibrotic lesions).

Conclusion: Our data suggests that male gender and higher SOFA score at intensive care unit admission were associated with pulmonary fibrosis in patients with severe COVID-19 pneumonia requiring mechanical ventilation.

Keywords: COVID-19; Idiopathic Pulmonary Fibrosis; Pneumonia.

Figure 1. Representative radiological findings of pulmonary fibrosis in study participants. (A) CT showing predominantly subpleural reticulation (arrow). (B) Honeycombing is indicated by the arrow in the right lower lobe. (C) Architectural distortion is indicated by the arrow in the left lower lobe. (D) Traction bronchiectasis and parenchymal band in the right lower lobe (black arrow) and left lower lobe (white arrow).

Figure 2. Automated quantification system evaluated by computer-based analysis of high-resolution CT imaging. GGO, ground glass opacities; MD, mixed disease; CON, consolidation.

Figure 3. Forest plot of HRs for risk factors for pulmonary fibrosis. BMI, Body Mass Index; WBC, white blood cell; BUN, blood urea nitrogen; SOFA, Sequential Organ Failure Assessment; ECMO, extracorporeal membrane oxygenation.