A year after recovery, it is common among patients with COVID-19 to have residual computed tomography (CT) abnormalities, especially fibrotic changes in patients who experienced severe COVID-19, according to results of a systematic review presented at the 2022 CHEST Annual Meeting, held from October 16 to 19, 2022, in Nashville, Tennessee.
Researchers conducted a retrospective systematic review and 1-group meta-analysis to measure the proportion of residual CT abnormalities at 1-year follow-up and the relationship between the time sequence of radiological sequelae and disease severity.
They searched the EMBASE and PubMed databases for studies that included CT findings at 1-year follow-up following COVID-19 treatment; some of these studies included mid-term follow-up data. Among 15 eligible studies (N=3134), there were 1495 patients who underwent CT 1 year following COVID-19, of whom 46.0% had residual CT abnormalities (95% CI, 32.7-59.4; I2=96.9%).
Fibrotic-like changes were observed in 26.1% (95% CI, 14.2-38.0; I2=94.6%) of patients and ground-glass opacity (GGO) was observed in 27.3% (95% CI, 20.1-34.4; I2=86.7%) of patients. The researchers noted no improvement from mid-term to follow-up in interlobular septal thickening (13.2% to 12.8%), bronchiectasis (12.5% to 13.3%), and fibrotic-like changes (14.9% to 26.1%). The proportion of GGO decreased from mid-term to 1-year follow-up (34.0% to 27.3%).
Patients with severe COVID-19 experienced a higher frequency of CT abnormalities at 1-year follow-up compared with patients with mild or moderate disease (54.8% [95% CI, 40.6-69.0] vs 32.2% [95% CI, 1.6-62.7]). Fibrotic-like changes were found in 30.4% among the patients with severe COVID-19 at 1-year follow-up.
At 1-year follow-up, 29.9% of patients had reduced diffusing capacity of the lung for carbon monoxide (DLCO) (<80% of predicted value) and 8.0% of patients had reduced total lung capacity (TLC). Consistent with other results, these pulmonary function test abnormalities were more frequent in severe cases than in mild or moderate cases (DLCO [30.1% vs 21.5%]; TLC [10.5% vs 5.6%]).
A limitation of the study is the retrospective design.
The study authors conclude, “Our meta-analysis indicated that residual CT abnormalities were common in COVID-19 patients 1 year after recovery, especially fibrotic changes in severe/critical cases. Physicians should be aware of the high frequency of lung sequelae even 1 year after COVID-19.”
Watanabe A, So M, Iwagami M, et al. One-year follow-up CT findings in patients with COVID-19: A systematic review and meta-analysis. Presented at: CHEST 2022 Annual Meeting; October 16-19, 2022; Nashville, TN.