Assessment of airway involvement in patients with inflammatory bowel disease

Objective: Ulcerative colitis (UC) and Crohn's disease (CD) are chronic inflammatory bowel diseases (IBD) that can affect not only the gastrointestinal system but also systemic organs. The aim of this study is to evaluate subclinical airway involvement in individuals with IBD using spirometry and impulse oscillometry (IOS). Materials and Methods: This study included 126 IBD patients (82 with CD, 44 with UC) and 28 healthy controls aged 18–65, all without a known diagnosis of airway disease. Participants underwent IOS followed by spirometry. A maximal mid-expiratory flow (MMEF) value below 65% was used to define small airway disease (SAD), and IOS parameters were comparatively evaluated. Results: The groups were similar in age, sex, and body mass index. Smoking history, passive exposure, family history of airway disease, and previous COVID-19 were more common in the patient group. Of the IBD patients, 38% were in the active phase. SAD was significantly more frequent in IBD patients than in controls (p = 0.006) and was higher in CD compared to UC (p = 0.032). In active CD, MMEF 25–75 (ml) was significantly lower than in controls. IOS parameters (R5, R5–R20, Fres, AX) were significantly elevated in patients with SAD. Conclusion: SAD is more common in IBD, particularly in CD and during active disease. Spirometry and IOS used together may offer a complementary and effective approach for detecting early airway involvement in IBD. Keywords: Inflammatory bowel disease, pulmonary function test, impulse oscillometry