Pulmonary fibrosis and its related factors in discharged patients with new coronavirus pneumonia: A cohort study of 90-150 days follow-up after onset

Background: The Coronavirus Disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a pandemic, posing a serious threat to public health worldwide. Whether survivors of COVID-19 pneumonia may be at risk of pulmonary fibrosis is still unknown. Methods: This study involves 462 laboratory confirmed patients with COVID-19 who were admitted to Shenzhen Third People’s Hospital. A total of 457 patients underwent thin-section chest CT scans during the hospitalization or after discharge to identify the pulmonary lesion. A total of 287 patients were followed up from 90 days to 150 days after the onset of the disease. Finding: 397 (86.87%), 311 (74.40%), 222 (79.56%), 141 (68.12%) and 49 (62.03%) patients developed with pulmonary fibrosis during the 0-30, 31-60, 61-90, 91-120 and >120 days after onset, respectively. Reversal of pulmonary fibrosis were found in 18 (4.53%), 61 (19.61%), 40 (18.02%), 54 (38.30%) and 24 (48.98%) COVID-19 patients during the 0-30, 31-60, 61-90, 91-120 and >120 days after onset, respectively. It was observed that Age, BMI, Fever, and Highest PCT were predictive factors for sustaining fibrosis even after 90 days from onset. Only a fraction of COVID-19 patients suffered with abnormal lung function after 90 days from onset. Interpretation: Long-term pulmonary fibrosis was more likely to develop in patients with older age, high BMI, severe/critical condition, fever, long time to turn the viral RNA negative, pre-existing disease and delay to admission. Fibrosis developed in COVID-19 patients could be reversed in about a half of the patients after 120 days from onset. The pulmonary function of most of COVID-19 patients with pulmonary fibrosis could turn to normal condition after three months from onset. Funding Statement: Shenzhen Science and Technology Research and Development Project (202002073000001 and 202002073000002), Shenzhen Fund for Guangdong Provincial High-level Clinical Key Specialties (SZGSP011). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: This study was conducted at Shenzhen Third People's Hospital and approved by the Ethics Committees, each patient gave written informed consent.