Pulmonary Fibrosis in Critically Ill Patients With COVID-19: A Multi-Center Retrospective Cohort Study in Korea

초록

Background: Pulmonary fibrosis can persist long after recovery from coronavirus disease 2019 (COVID-19) infection, thereby reducing quality of life and lung function. We aimed to evaluate the frequency and risk factors for pulmonary fibrosis in patients with severe COVID-19 pneumonia requiring mechanical ventilation (MV), a high-risk group for developing pulmonary fibrosis. Methods: Clinical data and chest computed tomography (CT) scans of patients with severe COVID-19 pneumonia requiring MV were retrospectively collected from nine hospitals in South Korea. Fibrotic-like changes on chest CT were visually assessed. Results: We included 125 patients with a mean age of 68.5 years, 60.8% men and 7.2% having underlying lung disease. Based on follow-up chest CT (the median interval, 38.0 days; interquartile range, 24.0-68.0 days), 94 (75.2%) patients exhibited fibrotic-like changes, with traction bronchiectasis and/or bronchiolectasis being the most common change (60.8%). Among all patients, 17.6% died during hospitalization and 71.2% experienced complications, including intubation-related airway injury (12.8%), ventilator-associated pneumonia (44.8%), lung injury (11.2%), and hemodynamic disturbance (33.4%). In-hospital mortality (16.1% vs. 18.1%) and complications (67.7% vs. 72.3%) were similar between patients with and without fibrotic-like changes. In multivariable logistic regression analysis, a higher daily steroid dose (odds ratio, 0.961; 95% confidence interval, 0.849-0.993; P = 0.018) was associated with a reduced risk of pulmonary fibrosis, along with a higher heart rate on intensive care unit admission. Conclusion: Our study demonstrated that in patients with severe COVID-19 pneumonia requiring MV, chest CT revealed fibrotic-like changes in approximately threequarters of patients. In addition, our results suggest that higher daily doses of steroids may be associated with a reduced risk of pulmonary fibrosis. Further research is needed to determine the appropriate steroid dose that may reduce the progression of pulmonary fibrosis and improve clinical outcomes.

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