Lung function of patients hospitalized with COVID-19 at 45 days after hospital discharge: first report of a prospective multicenter study in Brazil

Eliane Viana Mancuzo, Carolina Coimbra Marinho, George Luiz Lins Machado-Coelho, Aline Priscila Batista, Jacqueline Ferreira Oliveira, Bruno Horta Andrade, Álvaro Lucca Torres Brandão, Ana Sophia Mitre Leite, Pedro Chaves Ferreira, José Reinaldo Corrêa Roveda, Arnaldo Santos Leite, Valéria Maria Augusto

Because SARS-CoV-2 infection can severely affect the lungs and persistent functional changes can occur after severe disease, we aimed to determine lung function parameters of COVID-19 patients at 45 days after hospital discharge and compare changes according to the severity of the disease. This was a prospective descriptive analytical multicenter study. The participants were allocated into three groups: ward admission (WA) group; ICU admission not on mechanical ventilation (ICU/MV-) group; and ICU admission on MV (ICU/MV+) group. Lung volumes, DLco, MIP, MEP, and six-minute walk distance (6MWD) were measured 45 days after discharge. The sample comprised 242 patients (mean age = 59.4 ± 14.8 years; 52.1% of males), and 232 (96%) had altered lung function. In the total cohort, restrictive disorder was observed in 96%, as well as reductions in DLco (in 21.2% of the patients), FEV1/FVC (in 39.7%), and PEmax (in 95.8%), with no differences between the groups. Comparing the groups, the ICU/MV+ group had reduced DLco in 50% of the patients (p < 0.001) and a lower mean 6MWD % of the predicted value (p = 0.013). Oxygen desaturation in the six-minute walk test was observed in 32.3% of the cohort and was less frequent in the IE group. This is the first South American study involving severe COVID-19 survivors whose lung function was assessed 45 days after hospital discharge. Changes were frequent, especially in those on MV, which highlights the importance of lung function evaluation after severe COVID-19.