Lung-function trajectories in COVID-19 survivors after discharge: A two-year longitudinal cohort study

Hui Zhang; Xia Li; Lixue Huang; Xiaoyin Gu; Yimin Wang; Min Liu; Zhibo Liu; Xueyang Zhang; Zhenxing Yu; Yeming Wang; Chaolin Huang; Bin Cao

doi:10.1016/j.eclinm.2022.101668

Lung-function trajectories in COVID-19 survivors after discharge: A two-year longitudinal cohort study

EClinicalMedicine. 2022 Sep 28:54:101668. doi: 10.1016/j.eclinm.2022.101668. eCollection 2022 Dec.

Authors

Hui Zhang^{1

2}, Xia Li³, Lixue Huang^{1

2}, Xiaoyin Gu⁴, Yimin Wang^{2

5}, Min Liu⁶, Zhibo Liu², Xueyang Zhang⁷, Zhenxing Yu⁵, Yeming Wang^{2

8}, Chaolin Huang³, Bin Cao^{1

2

7

8}

Affiliations

¹ Department of Pulmonary and Critical Care Medicine, China-Japan Friendship hospital, Capital Medical University, Beijing, China.
² Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, National Clinical Research Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing, China.
³ Hubei Provincial Clinical Research Center for Infectious Diseases, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, Chinese Academy of Medical Sciences, Wuhan, China.
⁴ Department of Clinical Research and Data Management, Center of Respiratory Medicine, China-Japan Friendship Hospital; Institute of Respiratory Medicine, Chinese Academy of Medical Sciences; National Clinical Research Center for Respiratory Diseases, Beijing, China.
⁵ Department of Pulmonary and Critical Care Medicine, Hubei Provincial Clinical Research Center for Infectious Diseases, Wuhan Research Center for Communicable Disease Diagnosis and Treatment, Chinese Academy of Medical Sciences, Wuhan, China.
⁶ Department of Radiology, China-Japan Friendship Hospital, Beijing, China.
⁷ Tsinghua University School of Medicine, Beijing, China.
⁸ Changping Laboratory, Beijing, China.

Abstract

Background: Data on the long-term trajectories of lung function are scarce in COVID-19 survivors.

Methods: We re-analyzed the data from a prospective longitudinal cohort follow-up study of COVID-19 survivors over 2 years after infection. All participants were divided into scale 3, scale 4 and scale 5-6 groups according to seven-category ordinal scale. The changes of pulmonary function tests (PFTs), the Modified Medical Research Council (mMRC) Dyspnea Scale, 6-min walking test health-related quality of life (HRQoL) across the three serial follow-up visits were evaluated, and compared among three groups. We performed liner regression to determine potential factors that were associated with changes of PFTs and distance walked in 6 minutes (6MWD).

Findings: In this study, 288 participants generally presented an improvement of PFTs parameters from 6 months to 1 year after infection. The scale 5-6 group displayed a significantly higher increase of PFTs compared with scale 3 and scale 4 groups (all p<0.0167), and corticosteroids therapy was identified as a protective factor for the PFTs improvement with a correlation coefficient of 2.730 (0.215-5.246) for forced vital capacity (FVC), 2.909 (0.383-5.436) for total lung capacity (TLC), and 3.299 (0.211-6.387) for diffusion capacity for carbon monoxide (DLco), respectively. From 1-year to 2-year follow-up, the PFTs parameters generally decreased, which was not observed to be associated with changes of 6MWD and HRQoL. Dyspnea (mMRC≥1) generally decreased over time (23.3% [61/262] for 6-month, 27.9% [67/240] for 1-year, 13.4% [35/261] for 2-year), and 6MWD increased continuously (500.0 m vs 505.0 m vs 525.0 m).

Interpretation: Corticosteroids therapy during hospitalization was a protective factor for PFTs improvement from 6 months to 1 year. The relatively fast decline trend of PFTs from 1 year to 2 years needs to be paid attention and further validated in the future follow-up study.

Fundings: This work was supported by Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (CIFMS 2021-I2M-1-048) and the National Key Research and Development Program of China (2021YFC0864700).

Keywords: COVID-19; Corticosteroids; Long COVID; Lung function; Pulmonary function tests.