[Expert consensus on the management of interstitial lung disease during the COVID-19 epidemic]

Coronavirus disease 2019(COVID-19) is prevalent around the world, and pre-existing ILD is associated with increased severity and mortality of COVID-19. However, the current knowledge on the management strategy for COVID-19 patients with pre-existing interstitial lung disease (ILD) is very limited. There is still a need for consensus on treatments for these patients. In addition, ILD that occurs after the acute phase of COVID-19 (Post-acute Covid-19 ILD, PC-ILD) is also very common, and how to manage PC-ILD is also under debate. Therefore, a consensus was established by experts from the related disciplines in the field of ILD based on available scientific evidence and experience of the expert working group. This consensus elucidated 22 practical questions for practicing physicians, such as clinical characteristics, risk factors and treatment of COVID-19 patients with pre-existing ILD and PC-ILD patients. Finally, 15 recommendations were made regarding the diagnosis and management of COVID-19 patients with pre-existing ILD and PC-ILD patients. We hope to assist physicians in making appropriate decisions, thereby improving the management of COVID-19 with pre-existing ILD and PC-ILD.Recommendation 1: It is recommended to differentiate COVID-19 from ILD with acute/subacute onset based on duration, exposure history, symptoms and signs, chest high-resolution CT (HRCT) features, and laboratory tests.Recommendation 2: According to the guidelines on the diagnosis and treatment of new coronavirus pneumonia (version 10) issued by the National Health Commission of China on January 6^th, 2023, we recommended the following disease severity definition and management for the COVID-19 patients with pre-existing ILD.Recommendation 3: ILD is an independent risk factor for severe/critical COVID-19. We recommend antiviral treatment for COVID-19 patients with pre-existing ILD as early as possible after symptoms onset, ideally within 5 days.Recommendation 4: We recommend that the use of systemic corticosteroids in COVID-19 patients with pre-existing ILD who had no indications for corticosteroids therapy should follow the guidelines of COVID-19 for the general population. Those with pre-existing ILD who need to start or are already on systemic corticosteroids are recommended to start or continue corticosteroids if they develop COVID-19. The dose adjustment is based on the severity of COVID-19 with pre-existing ILD: For the patients with severe/critical COVID-19 with pre-existing ILD but no AE-ILD, the use of corticosteroids should follow the guidelines of COVID-19 in the general population; the patients with AE-ILD are recommended to follow the use of corticosteroids in AE-ILD.Recommendation 5: There is no evidence available for the use of interleukin-6 receptor blockers in COVID-19 patients with pre-existing ILD. Recommendations regarding interleukin-6 receptor blockers in COVID-19 patients with pre-existing ILD may follow the guideline of COVID-19 in the general population.Recommendation 6: There is no evidence to support the use of Janus kinase inhibitors in COVID-19 patients with pre-existing ILD. The use of Janus kinase inhibitors in COVID-19 patients with pre-existing ILD is recommended to follow the guideline of COVID-19 in the general population.Recommendation 7: For patients who have not started immunosuppressants/biological agents for pre-existing ILD at the time of COVID-19, delayed initiation of immunosuppressants/biological agents is recommended, if the risk of ILD progression in the short term is low. For patients who are already on immunosuppressants/biological agents, a multidisciplinary discussion with rheumatologists is recommended to weigh the benefits and risks of discontinuing immunosuppressants/biological agents. It is recommended to discontinue immunosuppressants/biological agents for pre-existing ILD in acute phase of COVID-19 unless short-term discontinuation affects control of underlying ILD or connective tissue disease.Recommendation 8: It is recommended that the COVID-19 patients with pre-existing ILD who are on anti-fibrotic medication should continue to take anti-fibrotic medication. For COVID-19 patients with newly diagnosed fibrotic ILD who need to start anti-fibrotic therapy, it is recommended to start anti-fibrotic treatment as early as possible.Recommendation 9: It is recommended to investigate and monitor co-infections and secondary infections in COVID-19 patients with pre-existing ILD, and to promptly prevent and treat co-infections and secondary infections such as bacteria, fungi, Pneumocystis jirovecii, and cytomegalovirus.Recommendation 10: Anticoagulation therapy for the COVID-19 patients with pre-existing ILD is recommended to be used in accordance with guideline of COVID-19 in general population.Recommendation 11: For COVID-19 patients with pre-existing ILD, we recommend follow-up at 4 weeks after recovery (non-hospitalized patients) or 4 weeks after discharge (hospitalized patients), and then the routine monitoring frequency for ILD once stable, i.e. every 3 to 6 months. Pulmonary function testing is a routine investigation. Chest HRCT is suggested when clinically indicated. Arterial blood gas analysis, echocardiography, CT pulmonary angiography, and blood examinations can be selected when necessary.Recommendation 12: Severe/critical COVID-19 survivors are the main target population for rehabilitation intervention. Rehabilitation therapy should be administered individualized.Recommendation 13: Healthcare providers should fully inform patients with pre-existing ILD about the benefits and risks of vaccination, and involve patients in a shared decision-making process to discuss whether or not to receive a COVID-19 vaccine.Recommendation 14: For PC-ILD patients with persistent or progressive respiratory symptoms, persistent interstitial lung abnormalities and lung function impairment following acute COVID-19 pneumonia, may be treated with glucocorticoids after exclusion of other causes such as infection.Recommendation 15: For PC-ILD patients who have recovered from severe/critical COVID-19, anti-fibrotic medications may be administered after discussing disease-and treatment-related factors with patients. The optimal timing and duration of anti-fibrotic treatment are still uncertain. We conditionally recommend against anti-fibrotic medications in patients who have recovered from mild or moderate COVID-19. This recommendation does not apply to patients with pre-existing fibrotic ILD.