Four-year respiratory consequences of COVID-19 related pneumonia: a longitudinal cohort study

Background We aimed to describe respiratory sequelae up to 4 years after discharge in COVID-19 patients with severe pneumonia having required non-invasive respiratory support therapies. Methods This study was conducted between March 2020 and June 2020 at University Hospital Doctor Josep Trueta (Girona, Spain). We assessed the patient’s dyspnoea and performed, pulmonary function tests, a high-resolution CT (HRCT), a 6-minute walking test, a blood test, and the Saint George’s respiratory questionnaire 3 months after discharge. At the 6-month, 1-year, and 4-year follow-up, we repeated all tests except for pulmonary function, 6-min walking test, and HRCT, which were only performed if abnormal findings had been previously detected. Results Out of the 94 patients enrolled, 73% were male, the median age was 62.9 years, and most were non-smokers (58%). When comparing data 3 months and 4 years after discharge, the percentage of patients presenting dyspnoea ≥ 2 decreased (19.5% vs 7.9%), the quality-of-life total score improved (22.8% vs 18.1%), diffusing capacity for carbon monoxide improved (75.9% vs 81.4%), the 6-min walking test distance was enhanced (368.0 m vs 436.6 m), ground glass opacities findings waned (56.6% vs 0.8%), and traction bronchiectasis increased (2.7% vs 9.2%). Age was the only parameter that exhibited significant differences between patients with and without pulmonary fibrotic-like changes. Conclusion Most patients, 4 years after discharge, improved their pulmonary function, exercise capacity, clinical condition, and quality of life. Although pulmonary fibrotic-like changes were observed during the follow-ups, its disparity with clinical-functional improvement pointed to non-progressive and non-clinically relevant lung scars.