Lung abnormalities persist in some patients 2 years after COVID-19 infection

Thirty-nine percent of patients who suffered a COVID-19 infection had interstitial lung abnormalities 2 years following the illness, according to study results published in Radiology.

“At 2-year follow-up, interstitial lung abnormalities (ILAs) or fibrotic ILAs were associated with persistent respiratory symptoms and decreased diffusion function,” Xiaoyu Han, MD, PhD, of the department of radiology at Union Hospital of Tongji Medical College, and colleagues wrote. “It may be possible that persisting residual symptoms and abnormal lung function, or further deterioration, is related to the patient's ongoing parenchymal lung damage.”

In a longitudinal, prospective single-center study, Han and colleagues analyzed 144 (median age, 60 years; 55% men) patients hospitalized with a SARS-CoV-2 infection but discharged between Jan. 15 and March 10, 2020, to look for differences in chest CT abnormalities and pulmonary function 2 years after the infection.

Researchers assessed patients’ chest CT scans, pulmonary function tests and responses to self-reported respiratory symptom questionnaires at three different time points: 6 months, 12 months and 2 years after symptoms started.

Of the total cohort, 23% of patients had fibrotic ILAs and 16% had nonfibrotic ILAs on the CT scans taken at 2 years, making for a total of 39% of patients with ILAs. The rest of the cohort had complete radiological resolution, according to researchers.

Looking at earlier CT scans, researchers found that ILAs among patients slowly declined over follow-up periods, from 54% at 6 months to 42% at 12 months to 39% at 2 years (P = .001).

In terms of lasting symptoms, researchers observed more respiratory symptoms in those with vs. without ILAs (34% vs. 15%; P = .007), notably cough (18% vs. 5.7%; P = .02) and exertional dyspnea (23% vs. 8%; P = .01).

Additionally, compared with patients who had complete radiological resolution, patients with ILAs had more diffusing capacity of the lung for carbon monoxide (DLCO) abnormalities (43% vs. 20%; P = .004).

Over the follow-up periods, the percentage of total patients with one or more respiratory symptom gradually went down (6 months, 30%; 12 months, 25%; 2 years, 22%), but researchers still observed 14% of patients with exertional dyspnea and 29% with mild and moderate pulmonary diffusion at 2 years.

Of those with ILAs, a greater number of patients with fibrotic ILAs experienced respiratory symptoms (45% vs. 17%; P = .03) and a reduced DLCO (60% vs. 22%; P = .005) compared with patients with nonfibrotic ILAs.

At 2 years, researchers saw higher percentages of interlobar pleural traction, thickening of the adjacent pleura, pulmonary atelectasis, bronchiectasis, honeycombing and parenchymal bands in patients than at baseline (P < .001), but these did not differ from 6 months to 2 years on CT scans.

“In particular, the proportion of fibrotic interstitial lung abnormalities, an important precursor to idiopathic pulmonary fibrosis, remained stable throughout follow-up,” Han and colleagues said in a press release from the Radiological Society of North America. “Therefore, the fibrotic abnormalities observed in our study might represent a stable, irreversible pulmonary condition, such as lung fibrosis, after COVID-19.”

Reference:

• Chest CT shows lung abnormalities two years after COVID. https://www.rsna.org/news/2023/february/lung-abnormalities-post-covid. Published Feb. 14, 2023. Accessed Feb. 14, 2023.