Assessment of long-term clinical and functional changes in patients recovering from severe COVID-19-associated lung damage

The problem of long COVID-19 (COronaVIrus Disease 2019) has been highly relevant for the healthcare system in the last three years. The persistence of respiratory symptoms, radiological and functional changes in COVID-19 patients brings new challenges to the entire medical community. The aim of the study is to explore long-term clinical and functional changes in patients with severe COVID-19-associated lung injury, including assessment of functional and radiological abnormalities of the respiratory system, as well as persistent clinical symptoms a year after the acute phase of the disease. Methods. The study included 45 patients who were examined 3, 6 and 12 months after COVID-19 with severe lung damage (more than 50% according to chest CT in the acute phase of the disease). Patients underwent multispiral computed tomography of the chest organs, a comprehensive study of respiratory function (spirography, body plethysmography and diffusion test); the clinical symptoms were assessed. Results. Chest CT scans showed gradual regression of pathological changes during the follow-up. However, radiographic changes of varying severity persisted after 12 months of follow-up in 51% of patients. A year later, restrictive disorders persisted in 20% of patients and the diffusion capacity of the lungs was reduced in 69% of patients. At the same time, a statistically significant difference in the DLСО level was observed between 3, 6 and 12 months. The severity of dyspnea decreased 1 year after hospitalization in 48% of patients. Conclusion. The obtained results demonstrate a gradual regression of both radiological and functional pathological changes during the 1st year. However, CT changes and deviations of the respiratory function persist in some patients, mainly in the form of a decrease in DLСО, which necessitates further monitoring of this group of patients.