Impact of COVID-19 Pneumonia on Chest Computed Tomography Scan and Spirometry During Six Months

Approximately a third of patients with SARS-CoV-2 have shown changes in respiratory function, impaired diffusion capacity for carbon monoxide, and persistent lung damage, one year after discharge. In severe COVID-19, patients may have a restrictive or obstructive defect in spirometry during and after recovery. One hypothesis is that respiratory symptoms in survivors might be attributable to pulmonary fibrosis. In this context, we evaluate spirometry and chest computed tomography (CT), 3 and 6 months after discharge, to further investigate the improvement of respiratory function in discharged patients with COVID-19.

This cohort study was conducted on 260 Iranian COVID-19 patients with a COVID-19 PCR-positive pneumonia. A chest CT scan was done at admission and 6 months after discharge. Also, a spirometry test was done 3 and 6 months after discharge. We used the Chi-Square test, t-test, Pearson's coefficient, and linear regression multivariate analysis by SPSS version 26.0 to analyze the data.

We identified that the most common chest CT scan abnormalities at presentation were ground glass opacities (GGO) (206 (79.23%)) and consolidation (183 (70.4%)). However, these sequelae were improved retrospectively 6 months after discharge to 17 (6.53%) and 16 (6.2%). The present study revealed abnormal spirometry in 81 (30.8%) cases in the 3rd month and 61 (23.9%) cases in the 6th month after acute COVID-19 pneumonia. There was a negative correlation between GGO score and spirometry parameters in both follow-ups (P values were < 0.016).

In summary, our study indicated that abnormal spirometry in the post-COVID-19 recovery phase is associated with a higher risk of long-term parenchymal lung disease, characterized by fibrotic-like changes in chest CT scans and smoking status, hypertension, and chronic kidney disease.