A Multicenter Study of Post-COVID-19 Interstitial Lung Syndrome

Introduction: Available data indicate that a large minority of patients with COVID-19 develop ARDS, and pulmonary fibrosis is a recognized sequela of ARDS. However, the long-term pulmo- nary consequences of COVID-19 remain speculative. Objects: The aim of this study is to evaluate risk factors, preva- lence and characteristics of POST-COVID-19 interstitial lung changes, with the unique opportunity to evaluate radiologic and pathologic correlations using HRCT and transbronchial lung cryobiopsy specimens. Methods: Here we present the preliminary data on HRCT fea- tures of POST-COVID-19 ILD. Data were collected at the time of the first interim analysis (28/11/2020) of the PCOILS trial: a pro- spective, multicenter national study involving 12 Italian centers (Fig 1). We collected data of consecutively hospitalized patients at baseline and then at 6 (+/-1) months after hospital discharge. HRCT changes at 6 months involving more than 5% of the total lung volume were considered significant. Patients with significant HRCT changes will undergo BAL and/or cryobiopsy and a subse- quent follow-up with HRCT and lung function evaluation at 12(+/-1) and 18 (+/-1) months. Results: At the time of the present interim analysis, 524 patients from 9 centers were enrolled (enrollment is still ongoing and will end on January 31st, 2021). Median age was 67 years (range 18-87), 330 were males (62.9%). HRCT changes were detected in 333 par- ticipants (63.5%), and in 219 (41.7%) were considered significant. 118 cases (22.5%) showed fibrotic changes including the following HRCT patterns: 7 (1.3%) probable UIP, 45 (8.5%) NSIP (with or without OP), 38 (7.2%) indeterminate, 28 (5.3%) fibrotic consoli- dations. Among the remaining 101 (19.2%) non fibrotic cases the radiologists described: 11 (2%) NSIP-OP, 15 (2.8%) indeterminate, 67 (12.7%) pure ground glass, 8 (1.5%) consolidations all suspected for lung cancer. Conclusions: This preliminary analysis confirms that after COVID-19 infection a large minority of patients develops intersti- tial lung changes mostly with NSIPOP, indeterminate features or ground glass. The hypothesis that post-COVID-19 interstitial changes and interstitial lung diseases may share common risk fac- tors, pathogenetic mechanisms and disease behaviour warrants further evaluations.