Trajectories of respiratory recovery after severe SARS-CoV-2 infection (RE2COVERI): a pragmatic, longitudinal cohort study.

International audienceBackground: Severe COVID-19 survivors may exhibit functional impairment, radiological sequelae and persistent symptoms at short to mid-term follow-up.Aims: To determine the trajectories of respiratory recovery after severe COVID-19, and factors that could influence it.Methods: Prospective, multicentre, longitudinal cohort study of adult patients hospitalized for severe COVID-19 (LOS ≥ 7d, oxygen flow ≥ 3L), evaluated at 3 months from hospital discharge with conditional follow-up at 6 and 12 months.Results: 486 participants from 13 French hospitals were included (median age 61y; female sex 27%): 173 needed oxygen only, 96 required non invasive ventilatory support and 217 were intubated. 454 (93%) patients were evaluated at 3 months, whereas 294 (60%) and 163 (34%) were followed up at 6 and 12 months, respectively. At 3-months assessment, a restrictive lung defect, an altered diffusion capacity and significant radiological abnormalities were observed in 33%, 71% and 57% of the cases, respectively. In case of extended follow-up, FVC (% pred.) increased by 4 points at M6 and by 7 points at M12, in mean; DLCO (% pred.) by 5 and 7 points, respectively. Age, sex, obesity, immunodepression, chronic cardiac or respiratory disease, initial extension of pneumonia and mechanical ventilation over 14 days were associated with lung function at 3 months but not with respiratory trajectories from this time point.Conclusion: A systematic follow-up seems justified after a severe COVID-19, especially in patients with extensive radiological lesions during acute illness. Pulmonary function and residual radiological abnormalities may improve up to 1-year after hospital discharge