Abstract Rationale Inflammatory bowel disease (IBD) is increasingly recognized as a systemic disorder, with extraintestinal manifestations (EIMs) involving multiple organ systems. Pulmonary involvement, particularly interstitial lung disease (ILD), remains an underrecognized manifestation of IBD. Its prevalence, clinical characteristics, and risk factors in IBD remain poorly defined. Methods We conducted a retrospective study of adults (≥18 years) with IBD who had at least one encounter in our health system between January 1, 2013 and December 31, 2023. IBD, and ILD cases were identified using ICD-9/ICD-10 codes, with ILD diagnoses confirmed by thoracic radiologists. Demographic, clinical, pulmonary, smoking, medication, and surgical data were abstracted. Associations between patient characteristics and ILD were evaluated using both a cohort design and a matched case-control design (1:3 ratio). Mortality was assessed using a Cox proportional hazards model with ILD as a time-dependent covariate. Results Among 875 patients with IBD, 109 (12%) had ILD. Radiographic patterns included nonspecific interstitial pneumonia (NSIP, 27%), indeterminate (26%), definite/probable UIP (24%), hypersensitivity pneumonitis (15%), and organizing pneumonia (8%). Pulmonary function testing demonstrated predominantly restrictive physiology and impaired diffusion capacity. In multivariable analysis, higher BMI (OR 1.04), bronchiectasis (OR 2.65), ex-smoking (OR 2.15), and use of adalimumab (OR 2.04) or infliximab (OR 2.14) were independently associated with ILD. The matched case-control design confirmed these findings and also identified older age (OR 1.04) as a significant factor. ILD was strongly associated with mortality (HR, 3.78; 95% CI, 2.50-5.72; p 0.001). Conclusions ILD occurs in a meaningful subset of patients with IBD and is associated with older age, higher BMI, prior smoking, bronchiectasis, and TNF inhibitor use. ILD confers a markedly increased risk of death, highlighting the importance of early recognition and close monitoring in this population. This abstract is funded by: None
Alarcon-Calderon et al. (2026) studied this question.