6-minute walk test in patients hospitalized with COVID-19

Introduction. The 6 Minute Walk Test (6MWT) plays a key role in assessing functional exercise tolerance and prognosis for a wide range of chronic respiratory and cardiovascular diseases. In acute bronchopulmonary diseases, in particular COVID-19, there is practically no data on the possibilities of using 6MWT.Aim. To compare the results of a 6-minute walk test with clinical and laboratory parameters of patients hospitalized with new coronovirus infection.Materials and methods. The prospective, non-randomized comparative study sequentially enrolled 117 patients hospitalized with a confirmed diagnosis of COVID-19. Upon admission to the hospital, all patients performed 6MWT in accordance with international recommendations.Results. During the 6-minute trial, patients walked an average of 390 m (340.0; 420.0). In 96.6% of patients, there was a marked limitation of physical activity. Desaturation during the 6-minute test was registered in 25 (21.4%) patients. When conducting a correlation analysis, it was found that the result of the test with physical activity (the number of meters traveled) is associated with both initial and final SpO2, the presence of desaturation and the severity of dyspnea according to Borg, with the age of patients, the severity of the course of new coronovirus infection, laboratory signs of the activity of the inflammatory process upon admission. Relationships between the results of 6MWT (the number of meters covered and the % decrease in SpO2) and the duration of hospitalization, the maximum volume of lung damage according to CT data, the maximum severity of laboratory signs of inflammation (CRP, ferritin) during hospitalization, the need for oxygen therapy, the volume of anti-inflammatory therapy (doses of systemic glucocorticoids, pulse therapy with methylprednisolone). Patients with desaturation during exercise had a more severe course of the disease with a large amount of lung tissue damage, as well as higher laboratory indicators of the activity of the inflammatory process. It was also found that patients who desaturate during the exercise test more often required oxygen therapy during hospitalization, more often pulse therapy with methylprednisolone was performed.Conclusion. Patients with COVID-19 develop a decrease in physical performance, which is multifactorial. These include respiratory failure due to lung tissue damage, muscle weakness, nervous system damage (anxiety, depression), and systemic inflammation, which characterizes the severity of the infection and the associated immune response. The results of 6MWT may have a certain prognostic value in terms of the severity of the course of the disease, the severity of systemic inflammation, the need for oxygen therapy, and pulse therapy with glucocorticoids.