Long-term radiological and pulmonary function abnormalities at 3 years after COVID-19 hospitalisation: a longitudinal cohort study
Xiaoyu Han, Lu Chen, Li-Yan Guo, Linxia Wu, Osamah Alwalid, Jie Liu, Yuting Zheng, Leqing Chen, Wenlong Wu, Hanting Li, Qinyue Luo, Huangxuan Zhao, Lijie Zhang, Yaowei Bai, Bo Sun, Tao Sun, Yuxi Gui, Tong Nie, Lei Chen, Fan Yang, Yanqing Fan, Heshui Shi, Chuansheng Zheng
Abstract
Background This study aimed to evaluate the longitudinal progression of residual lung abnormalities (ground-glass opacities, reticulation and fibrotic-like changes) and pulmonary function at 3 years following coronavirus disease 2019 (COVID-19). Methods This prospective, longitudinal cohort study enrolled COVID-19 survivors who exhibited residual lung abnormalities upon discharge from two hospitals. Follow-up assessments were conducted at 6 months, 12 months, 2 years and 3 years post-discharge, and included pulmonary function tests, 6-min walk distance (6MWD), chest computed tomography (CT) scans and symptom questionnaires. Non-COVID-19 controls were retrospectively recruited for comparative analysis. Results 728 COVID-19 survivors and 792 controls were included. From 6 months to 3 years, there was a gradual improvement in reduced diffusing capacity of the lung for carbon monoxide ( D LCO <80% predicted: 49% versus 38%; p=0.001), 6MWD (496 versus 510 m; p=0.002) and residual lung abnormalities (46% versus 36%; p<0.001), regardless of disease severity. Patients with residual lung abnormalities at 3 years more commonly had respiratory symptoms (32% versus 16%; p<0.001), lower 6MWD (494 versus 510 m; p=0.003) and abnormal D LCO (57% versus 27%; p<0.001) compared with those with complete resolution. Compared with controls, the proportions of D LCO impairment (38% versus 17%; p<0.001) and respiratory symptoms (23% versus 2.2%; p<0.001) were significantly higher in the matched COVID-19 survivors at the 3-year follow-up. Conclusions Most patients exhibited improvement in radiological abnormalities and pulmonary function over time following COVID-19. However, more than a third continued to have persistent lung abnormalities at the 3-year mark, which were associated with respiratory symptoms and reduced diffusion capacity.