Post-COVID-19 Interstitial Lung Disease: a new entity, what do we deal with?

ABSTRACT

Introduction: In the post-acute phase, COVID-19 survivors may have persistent symptoms, lung function abnormalities and sequela lesions on thorax CT. This new entity is defined as post-COVID Interstitial Lung Disease (ILD) or a residual disease. Aim(s) To investigate the characteristics and clinical significance of post-COVID-19 ILD. Method(s) Patients with persistent respiratory symptoms after recovery were evaluated by a team including two pulmonologists and a radiologist. Pulmonary function tests, 6-minute walking test, thorax HRCT were performed. Post-COVID ILD was defined as presence of all the followings respiratory symptoms, hypoxemia, restrictive lung functions and interstitial changes on follow-up HRCT. Result(s) A total of 375 post-COVID-19 patients were evaluated on average 91 days after recovery and 262 of them were included. 17.9 % of the patients were non-hospitalized with mild COVID-19;10.8 % of the patients had received high flow nasal oxygen, of 17.5 % had required non-invasive mechanical ventilation, of 8.8 % had been intubated. The most prevalent symptoms were dyspnoea, exercise intolerance and fatigue. The mean mMRC score was 1.82, oxygen saturation was 94.1, 6-minute walking distance was 374 meters. Pulmonary functions (percentage of mean predicted value +/- SD) were as follows;FEV179+/-19, FVC 73+/-19, FEV1/FVC 87+/-9, DLCO 64.5+/-21.8. On CT, GGOs, fibrotic bands, and a combination of them were detected. The mean CT score was 13.5. Discussion(s) The presence of symptoms and functional defects in addition to radiological parenchymal lesions requires the definition of this new entity is post-COVID-19 ILD which could be seen even in non-hospitalised patients with mild COVID-19.