Some patients who recover from Covid pneumonia still show lung abnormalities on chest CT scan after one year, according to a new study conducted at four medical centers in Austria.  

Luger et al conducted a secondary analysis of 142 patients with mild to severe Covid-19 from the CovILD study, which examined pulmonary recovery after the first wave of the pandemic from April 29, 2020 to August 12, 2020. All patients, mean age 59 years, were regularly followed up at 2, 3 and 6 months and 1 year after the onset of symptoms to determine the long-term course of pulmonary involvement following COVID-19 pneumonia. Patients were subjected to low-dose chest CT scans at each follow up visit. A qualitative CT severity score (CTSS) ranging from 0 to 25 was used to grade lung findings. The maximum score was 25 (5 per lobe maximum).

Follow up CT scans at one year were available for 91 participants, who were included in the final analysis. Only two of the 49 participants with CT abnormalities had been managed as outpatients; 51% had been hospitalized in general hospital ward, while 45% were admitted to ICU. 95% of patients receiving intensive care were intubated.

More than half of them (54%; 49 of 91) had lung abnormalities on CT scan mainly in the form of ground-glass opacities (GGO) and subpleural reticulations. GGOs and subpleural reticulations were present in 40 patients (44%) each; 9 (10%) had bronchial dilation and 4 had subpleural curvilinear lines (4.4%). After a year, slight subpleural reticulation and ground-glass opacities were seen on chest CT in 31 patients (34%). The remaining 18 (20%) had widespread ground-glass opacities (GGOs), reticulations, bronchial dilation and/or microcystic changes. Of these, Honeycombing pattern, illustrative of pulmonary fibrosis, was not seen in any patient.

The CT lung abnormalities completely resolved in 40 of 91 (44%) study subjects; but, 31 of 49 patients (63%) continued to show abnormalities after 6 months.

Older adults, aged 60 years and above, and male patients had a significant association with  persistent CT abnormalities at one year with odds ratio of 5.8 and 8.9. Critically ill patients were at high risk of having persistent CT abnormalities at 1 year (OR 29).

These findings published in the journal Radiology demonstrate high prevalence of lung abnormalities on CT chest even after one year of Covid-19 pneumonia suggesting permanent lung damage. And not just the critically ill patients, older patients and male patients were also shown to be at greater risk of having residual lung abnormalities. However, the authors say, “it is currently unclear if they represent persistent scarring, and whether they regress over time or lead to pulmonary fibrosis.” Long-term follow up of these patients is of utmost importance to fully evaluate the course of these lesions.

Patients should be enquired about symptoms such as dyspnea, reduced exercise capacity. Lung functions should also be determined in such patients and regularly monitored.

Reference

1. Luger AK, et al. Chest CT of lung injury 1 year after COVID-19 pneumonia: the CovILD study. Radiology. 2022 Mar 29;211670. doi: 10.1148/radiol.211670.