Background: COVID-19 is a new and highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, there is a paucity of data regarding long-term CT findings and pulmonary function in COVID-19 survivors. The aim of this study was to investigate the influence of COVID-19 pneumonia on pulmonary function and chest high-resolution computed tomography (CT) in convalescent patients.
Methods: A retrospective study of COVID-19 pneumonia patients in the Beijing Youan Hospital, Capital Medical University, was conducted. Serial assessments, including pulmonary volumes (TLC), spirometry (VC, FVC, FEV1), pulmonary diffusing capacity for carbon monoxide (DLCO, DLCO/VA), and chest high-resolution CT were collected 3 months after discharge.
Results: Forty-six patients completed the serial assessments. There were 38 non-severe and 8 severe cases. Abnormalities were detected in pulmonary function tests in 17 patients (37.8%). One (2.2%), 2 (4.3%), and 17 (37.8%) patients had FEV1/FVC ratio, TLC, and DLCO values less than 80% of predicted values, respectively. Twenty-eight patients (60.9%) had abnormal CT findings. Compared with patients with non-severe disease, those with severe disease had higher chest CT scores but a similar incidence of DLCO impairment. Similarly, patients who received glucocorticoids had higher chest CT scores but a similar incidence of DLCO impairment than those in the nonglucocorticoid group.
Conclusions: Three months after discharge from the hospital, impaired diffusing capacity and CT abnormalities were detected in more than one third of COVID-19 patients. Compared with patients with non-severe disease, those with severe illness had a higher incidence of lung imaging abnormalities and similar lung function impairment.