Risk factors associated with COVID-19 pneumonia in Chinese patients with pre-existing interstitial lung disease during the SARS-CoV-2 pandemic.

In China, the emergence of a nationally widespread epidemic infection of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has appeared within a month since December 7, 2022. To evaluate the risk factors for suffering from coronavirus disease 2019 (COVID-19) pneumonia due to infection with SARS-CoV-2 in different kinds of interstitial lung disease (ILD) patients with diverse immunizations, we conducted this retrospective study on 525 patients with ILDs who underwent regular follow-up in our ILD clinic. Among them, 128 ILD patients (24.4%) suffered from COVID-19 pneumonia after SARS-CoV-2 infection. Patients were older with a male predominance in the pneumonia group than in the nonpneumonia group (65.0 ± 10.0 years vs. 56.4 ± 11.7 years, p < 0.001, 55.5% vs. 39.5%, p = 0.002, respectively). Connective tissue disease-associated ILD (CTD-ILD) (25%), idiopathic pulmonary fibrosis (23.4%), and interstitial pneumonia with autoimmune features (21.1%) were the main pre-existing ILDs in the pneumonia group. In Cox multivariable analysis, only male sex and corticosteroid use were risk factors for COVID-19 pneumonia after infection. Two or three doses of vaccination were a protective factor for pre-existing ILD patients suffering from COVID-19 pneumonia. More than two doses of vaccination were strongly recommended for pre-existing ILD patients, particularly for males who were administered corticosteroids.