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

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;FEV1:79+/-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.

Methylprednisolone in the treatment of post-COVID-19 Interstitial Lung Disease (STERCOV-ILD)

Introduction: Post-COVID-19 Interstitial Lung Disease (ILD) is controversial and need for treatment is unclear. Aim(s): To investigate the efficacy of methylprednisolone in the treatment of post-COVID-19 ILD. Method(s): This multicentre, prospective, randomized controlled clinical trial, included post-COVID ILD patients (ClinicalTrials.gov, NCT:04988282). Post-COVID ILD was defined as the presence of respiratory symptoms, hypoxemia, restrictive lung functions and parenchymal infiltrates on thorax HRCT. 262 post-COVID-19 patients were randomly assigned to one of two arms: the steroid group (n:135) or control group (n:127). For 4 weeks, the steroid group received oral methylprednisolone at a dose of 0.5 mg/kg/day (maximum dose: 48 mg/day). At the end of the study, thorax HRCT, 6-minute walking test and lung function tests were re-evaluated. A good response was defined as a mMRC score of 0, a FVC percentage greater than 80% and absence of hypoxemia at rest or during exercise, greater than 90% resolution of lesions on CT. Result(s): Good clinical and functional response rates were higher in steroid group compared to the control group (62.9% vs 33.3%;54.1% vs 33.7%, p<0.001, respectively). Patients with a radiological response in steroid group tend to be higher than control group, but not statistically significant (61.1 % vs 51.1 %, p=0.159). The increase in oxygen saturation, FVC, and 6-minute walking distance were significantly higher in the steroid group compared to the control. Discussion(s): Systemic corticosteroids improves clinical and functional characteristics and increases oxygen saturation, FVC, and exercise capacity in post-COVID ILD patients compared to the natural course of the disease.