Evolution over time of lung involvement in severe-critical COVID-19 pneumonia survivors: the non-steroid approach.

<bold>Introduction:</bold> The long-term effects of pulmonary involvement in survivors of COVID-19 disease and the need for treatment are poorly described. <bold>Aim:</bold> To investigate the natural history of lung involvement in severe-critical COVID-19 pneumonia survivors post-discharge without antifibrotics, corticosteroids or other immunomodulators. <bold>Methods:</bold> A prospective, follow-up study of severe-critical COVID-19 survivors discharged from March 2020 to October 2022, assessed at 3 and 6 months. Evaluation included chest HRCT, pulmonary function tests, dyspnea scale (mMRC), quality of life questionnaire (SGRQ). Severe-critical disease was defined by the extent of pneumonia on CT during the acute phase (>50% extent) and/or respiratory support (FiO2≥50% or HFNC or IMV). <bold>Results:</bold> 198 patients (61% males) with median age 57 years (IQR 49-66). At 3 months 187 patients (94%) were assessed and at 6 months 82 (41%). There was a statistically significant reduction on the extent of pulmonary opacities (p <0.001) and parenchymal bands (p 0.014) in serial CT scans. 18 (9%) patients had fibrotic-like changes (2 findings mainly in apices, 14 fibrotic NSIP and 2 NSIP-minimal findings). At 3 months, the median FEV1 and FVC were 93% (80-100) (71% normal, 23% restrictive, 6% obstructive pattern) and DLCO 65% (58-78) with a statistically significant improvement at 6 months (p<0.001). At 3 months, 81% had mMRC≤1 and median SGRQ 12 [0-24] with a significant reduction in dyspnea levels and SGRQ at 6 months (p<0.001). <bold>Conclusion:</bold> The present study highlights the radiological, clinical and functional improvement observed after severe-critical COVID-19 pneumonia without the need for specific treatment.