Open Access

This study aims to report real-life data on the characteristics and treatment patterns of patients with fibrosing interstitial lung disease (ILD; except idiopathic pulmonary fibrosis) across multiple specialised centres in Germany. Eligibility criteria included ILD affecting >10% of lung parenchyma on high-resolution computed tomography, a single breath diffusion capacity for carbon monoxide (DLCO) ≤80% predicted and active treatment of lung disease. Methods As of the interim analysis cut-off, 655 patients (mean±sd age 65.9±11.7 years, 54.5% male) were included. The most common ILD subtypes were fibrosing hypersensitivity pneumonitis (31.2%), fibrosing ILD (22.0%), rheumatoid arthritis and connective tissue disease ILDs (13.0%) and unclassifiable fibrosing ILD (13.0%). Results Lung function metrics included total lung capacity at 68.3±17.6% predicted, forced vital capacity at 69.8±19.8% predicted, forced expiratory volume in 1 s at 73.7±19.5% predicted and DLCO at 33.8±15.6% predicted. Current treatments included oral steroids (62.6%), antifibrotic therapy (50.7%), azathioprine (14.4%), methotrexate (10.2%) and mycophenolate mofetil (11.1%). Patients on antifibrotic therapy were typically older at diagnosis and registry inclusion, more often male, had more comorbidities, a lower 6-min walk distance and reduced lung function metrics compared with those not on antifibrotic therapy. Notably, 27.3% of the patients on antifibrotic therapy did not meet progression criteria (INBUILD), whereas 40.1% of patients not receiving antifibrotic therapy did meet those criteria. Conclusion The patient characteristics observed align with those observed in randomised controlled trials and other noninterventional studies. Patients on antifibrotic therapy generally had more severe disease profiles.