B41-16 Patient Characteristics and Underlying Etiologies in Progressive Pulmonary Fibrosis: A Real-World U.S. Cohort Analysis

Abstract Introduction Progressive pulmonary fibrosis (PPF) includes non-idiopathic pulmonary fibrosis (non-IPF) interstitial lung diseases (ILDs) that develop a progressive, irreversible fibrotic course similar to IPF. The recent adoption of PPF terminology has unified recognition of progressive fibrotic behavior across diverse ILDs, yet large real-world characterizations of this population remain limited. A clearer understanding of these patients can guide diagnostic accuracy, inform guideline implementation, and support future therapeutic research. This study aimed to describe the demographic and clinical characteristics, as well as the underlying etiologies, of patients diagnosed with PPF within a large, real-world U.S. cohort identified through ICD-10 coding. Methods This retrospective observational study used the TriNetX Research Network, containing de-identified electronic health record data from 72 U.S. healthcare organizations (2019-present). Adults with PPF were identified using ICD-10 code J84.170 (“Interstitial lung disease with progressive fibrotic phenotype”). The index event was the first recorded diagnosis of PPF. Demographic and clinical characteristics were assessed during the five years preceding and including the index event. Related ICD-10 codes representing the same condition (e.g., variants of rheumatoid arthritis, systemic sclerosis, or myositis) were combined into single diagnostic categories to improve capture accuracy. Analyses were descriptive, reporting means, medians, and proportions for demographic and clinical variables. Results A total of 3,668 patients with PPF were identified (mean age 70 ± 13.7 years; median 72, IQR 16); 55% were female. The majority were White (69%), followed by Black (18%) and Asian (4%). Idiopathic ILDs were common, including idiopathic pulmonary fibrosis (n = 697), idiopathic NSIP (n = 71), and other idiopathic interstitial pneumonias (n = 225) such as cryptogenic organizing pneumonia (COP), respiratory bronchiolitis-ILD (RB-ILD), acute interstitial pneumonitis (AIP), desquamative interstitial pneumonia (DIP), and lymphoid interstitial pneumonia (LIP), totaling 993 (27%) patients. Autoimmune-associated ILDs included rheumatoid arthritis (n = 1,016), systemic sclerosis (n = 506), dermatomyositis/polymyositis (n = 483), and systemic lupus erythematosus (n = 227). Coexisting pulmonary conditions were frequent: secondary pulmonary hypertension (1,305; 36%), chronic respiratory failure (1,157; 32%), COPD (1,056; 29%), and bronchiectasis (1,046; 29%). Conclusions In this large, real-world U.S. cohort, PPF was commonly associated with autoimmune and idiopathic ILD etiologies. The presence of nearly 700 patients coded for idiopathic pulmonary fibrosis within the PPF cohort suggests potential overlap or miscoding, reflecting both evolving use of the new PPF code and persistent diagnostic inaccuracy. These findings highlight ongoing gaps in recognition, coding, and diagnostic precision in EHR-based research. This abstract is funded by: None