Journal Article

Clinical implications of traction bronchiectasis in IPF and fibrotic RA-ILD – a retrospective single-center cohort study

Fuge, Jan, Dettmer, Sabine, Ringshausen, Felix C, Schupp, Jonas C, Prasse, Antje, Rademacher, Jessica, Ruwisch, Jannik, Drick, Nora, Graalmann, Theresa, Hoeper, Marius M, Seeliger, Benjamin, Raith, Jakob, Knegendorf, Leonard

2026

Overview

Background Bronchiectasis is a common feature in idiopathic pulmonary fibrosis (IPF) and rheumatoid arthritis-associated interstitial lung disease (RA-ILD). While these so-called traction bronchiectasis are often considered a secondary phenomenon in fibrosing ILD, their prognostic significance and relationship to respiratory pathogen detection and outcomes remain unclear. Methods We conducted a retrospective, single-center cohort study in IPF or fibrosing RA-ILD patients with available high-resolution computed tomography (HRCT) and lower-respiratory tract microbial samples between 2014 and 2024. Bronchiectasis was assessed using the bronchiectasis subscore of the Brody score; fibrosis was quantified by deep-learning–based automated HRCT analysis. Primary outcome was 5-year transplant-free survival; secondary outcomes included isolation of pathogens per CDC criteria, PFT trajectories, bronchiectasis-associated symptoms, and hospitalization. Statistical methods included Cox regression, linear mixed-effects modeling and correlation analysis. Results 267 IPF and 56 RA-ILD patients were included. Median modified Brody score was 11.5 (IQR 7–16; max possible range 0–72). Higher Brody scores strongly correlated with fibrotic extent ( R  = 0.6, P  < 0.001). Higher scores had significantly lower baseline FVC and DLCO ( P  < 0.001), but no differences in PFT trajectories over time. In multivariable Cox regression, higher bronchiectasis scores were independently associated with mortality (HR 1.03 per point [95%CI 1.01–1.06], P  = 0.003); fibrosis extent showed similar results (HR 1.02, CI 1.00–1.03, P  = 0.017). Pathogens were found at a median of 3 months after baseline in 50.9% (IPF) and 46.4% (RA-ILD), without association with survival, symptoms or Brody scores. Staphylococcus aureus was most common (28.9%); Pseudomonas aeruginosa was rare (1.9%). Conclusion In both IPF and RA-ILD, higher bronchiectasis scores were associated with fibrosis extent and mortality, but not classical clinical bronchiectasis features. This supports traction bronchiectasis as a marker of fibrotic remodeling rather than a distinct syndrome. Trial registration Not applicable.

• Publisher: BioMed Central,BioMed Central Ltd,Nature Publishing Group,BMC
• Subject: Aged / Arthritis, Rheumatoid - complications / Arthritis, Rheumatoid - diagnosis / Arthritis, Rheumatoid - diagnostic imaging / Arthritis, Rheumatoid - epidemiology / Bronchiectasis / Bronchiectasis - diagnosis / Bronchiectasis - diagnostic imaging / Bronchiectasis - epidemiology / Bronchiectasis - etiology / Bronchiectasis - mortality / Bronchiectasis - physiopathology / Bronchiectasis, Fibrosis / Cohort Studies / Complications and side effects / Computed tomography / Correlation analysis / Deep learning / Female / Fibrosis / Humans / Idiopathic Pulmonary Fibrosis - complications / Idiopathic Pulmonary Fibrosis - diagnosis / Idiopathic Pulmonary Fibrosis - diagnostic imaging / Idiopathic Pulmonary Fibrosis - epidemiology / Idiopathic Pulmonary Fibrosis - physiopathology / IPF / Lavage / Lung diseases / Lung diseases, Interstitial / Lung Diseases, Interstitial - complications / Lung Diseases, Interstitial - diagnosis / Lung Diseases, Interstitial - diagnostic imaging / Lung Diseases, Interstitial - epidemiology / Male / Medical laboratories / Medical research / Medicine / Medicine & Public Health / Medicine, Experimental / Microorganisms / Middle Aged / Mortality / Pathogens / Patients / Physiological aspects / Pneumology/Respiratory System / Pneumonia / Pulmonary fibrosis / RA-ILD / Respiratory tract / Retrospective Studies / Rheumatoid arthritis / Rheumatoid factor / Risk factors / Signs and symptoms / Statistical analysis / Statistical methods / Survival / Tomography / Tomography, X-Ray Computed