Chest CT scans reveal lung abnormalities in patients 2 years after Covid: Study

PTI, Feb 16, 2023, 10:01 AM IST

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Chest CT scans revealed persistent lung abnormalities in patients two years after COVID-19, according to a new study.

Globally, more than 600 million people have recovered from COVID-19, but concerns remain that some organs, especially the lungs, may suffer long-term damage after infection, the study said.

This is the first research paper with two-year follow-up data on COVID-19 lung effects, it said. It is published in the journal Radiology.

According to the paper, Qing Ye and Heshui Shi from Tongji Medical College of Huazhong University of Science and Technology in Wuhan, China, and colleagues set out to assess residual lung abnormalities in patients up to two years post-COVID-19 pneumonia.

They also looked at the correlation between residual lung abnormalities and changes in lung function, the study said.

In this prospective study, it said, 144 patients, 79 men and 65 women with a median age of 60, discharged from the hospital after SARS-CoV-2 infection between January 15 and March 10, 2020, were included.

Three serial chest CT scans and pulmonary function tests were obtained at six months, 12 months and two years after symptom onset, the study said.

Residual lung abnormalities after discharge from the hospital included fibrosis (scarring), thickening, honeycombing, cystic changes, dilation of the bronchi, and more, the study found.

The study also found that over two years, the incidence of lung abnormalities gradually decreased. At six months, 54 per cent of patients showed lung abnormalities.

On two-year follow-up CT scans, 39 per cent, or 56 of the patients, had lung abnormalities, including 23 per cent, or 33 patients, with fibrotic lung abnormalities and 16 per cent, or 23 patients, with non-fibrotic lung abnormalities, the study reported.

”In particular, the proportion of fibrotic interstitial lung abnormalities, an important precursor to idiopathic pulmonary fibrosis, remained stable throughout follow-up,” the authors said.

”Therefore, the fibrotic abnormalities observed in our study might represent a stable, irreversible pulmonary condition, such as lung fibrosis, after COVID-19,” the authors said.

The remaining 88 cases, or 61 per cent of the participants, showed no abnormalities, the study said.

Patients with lung abnormalities on CT were more likely to have respiratory symptoms and abnormal lung function, the study said.

The proportion of individuals with respiratory symptoms decreased from 30 per cent at six months to 22 per cent at two years, the study said.

At two-year follow-up, the most common respiratory symptom was exertional dyspnea or shortness of breath, observed in 14 per cent of the study group, while mild and moderate pulmonary diffusion were observed in 29 per cent, or in 38 out of 129 of the patients, the study said.

Pulmonary diffusion refers to how well the air sacs in the lungs are delivering oxygen to and removing carbon dioxide from the blood in the tiny blood vessels that surround them.

Pulmonary diffusion was regarded as abnormal when diffusing capacity of the lung for carbon monoxide was less than 75 per cent of the predicted value, the study said.

The researchers suggested that persisting residual symptoms and abnormal lung function could be related to the patient’s ongoing lung damage.

”Long-term and functional consequences of chest CT findings post-COVID-19 are largely unknown,” the authors said.

”Our prospective study found that 39 per cent of participants had persistent interstitial lung abnormalities at two-year follow-up, which were associated with respiratory symptoms and decreased diffusion function,” the authors said.

The authors advised that patients with residual lung abnormalities or respiratory symptoms after COVID-19 should be followed up to detect and manage pulmonary changes and functional impairment.