Three-month pulmonary function and radiological outcomes in COVID-19 survivors: a longitudinal patient cohort study

Liao, Xuejiao; Wang, Ying; He, Ziyi; Yun, Yongxing; Hu, Ming; Ma, Zhenghua; Huang, Ling; Cai, Qingxian; Xu, Lin; Hao, Yuantao; Liu, Lei

BACKGROUND: This study aimed to investigate pulmonary function and radiological outcomes in a group of coronavirus disease 2019 (COVID-19) survivors. METHODS: 172 COVID-19 survivors in a follow-up clinic in a referral hospital underwent high resolution computed tomography (CT) of the thorax and pulmonary function tests at three month after hospital discharge. RESULTS: The median duration from hospital discharge to radiological and pulmonary function test was 90 (interquartile range=88-95) days. The abnormal pulmonary function was found in 11 (6.40%) patients, and abnormal small airway function (FEF(25-75%)) in 12 (6.98%). Six (3.49%) patients had obstructive ventilation impairment and six (3.49%) had restrictive ventilatory impairment. No significant differences in lung function parameters were observed between the non-severe and severe groups. Of 142 COVID-19 patients performed CT scan, 122 (85.91%) showed residual CT abnormalities and 52 (36.62%) showed chronic and fibrotic changes. The ground-glass opacities absorption in the lungs of severe cases was less satisfactory than that of non-severe patients. The severe paients had higher CT scores than non-severe cases (2.00 versus 0.00, P < 0.001) CONCLUSION: Of the COVID-19 survivors, 6.40% still present pulmonary function abnormality three month after discharge, which did not vary by disease severity during hospitalization. 85.91% patients had abnormalities on chest CT, with fibrous stripes and ground glass opacity as the most common pattern.