Radiologic Pattern of Fibrosis in Combined Pulmonary Fibrosis and Emphysema: Impact on Disease Trajectories and...

Background Combined pulmonary fibrosis and emphysema (CPFE) presents with heterogeneous radiologic patterns, but its impact on disease progression and clinical outcomes remains poorly understood. Purpose To evaluate the impact of different fibrosis patterns on disease trajectory and outcomes in patients with CPFE. Materials and Methods This retrospective study included patients who underwent high-resolution CT between January 2011 and December 2021, with CPFE defined as emphysema (any subtype) involving at least 5% of total lung volume and fibrosis at CT, and who had available follow-up data. Radiologic fibrosis patterns were classified as usual interstitial pneumonia (UIP) and/or probable UIP (radiologic UIP) or as other patterns, including nonspecific interstitial pneumonia (NSIP), smoking-related interstitial fibrosis (SRIF), and desquamative interstitial pneumonia (DIP). Deep learning-based quantification was used to assess the extent of emphysema and fibrosis. Longitudinal outcomes were analyzed using the Cox proportional hazards models. Results A total of 236 patients with CPFE were included (mean age, 65 years ± 7.8 [SD]; 232 men). Of the 236 patients, 99 (41.9%) were classified with UIP, 73 (30.9%) with NSIP, 48 (20.3%) with SRIF, 14 (5.93%) with DIP, and two (0.85%) with an unclassifiable pattern. Radiologic fibrosis patterns were associated with the rate of fibrotic progression, which was fastest in UIP (median, 1.2 years), followed by NSIP (median, 2.1 years), and slowest in SRIF or DIP (median, 3.0 years; P < .001). However, radiologic fibrosis patterns were not significantly associated with emphysema progression (univariable P = .27), lung transplant-free survival (multivariable P = .55), time-dependent lung cancer (multivariable P = .65), or acute exacerbation (multivariable P = .64). Greater baseline fibrosis extent (adjusted hazard ratio [HR]: 1.04; 95% CI: 1.02, 1.06), lung cancer (adjusted HR: 3.90; 95% CI: 2.55, 5.96), and acute exacerbation (adjusted HR: 4.31; 95% CI: 2.68, 6.94) were associated with worse survival. Conclusion In patients with CPFE, radiologic fibrosis patterns were associated with the rate of fibrosis progression, whereas survival was primarily determined by baseline fibrosis extent and adverse clinical events, including the development of lung cancer. © The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article.