Background: Pulmonary involvement due to inflammatory bowel disease (IBD) is frequent when evaluating a patient with IBD and pulmonary involvement remains complicated. Most of the patients are asymptomatic and the methods used are mostly invasive or expensive procedures. The aim of this prospective study is to evaluate the value of the fractional exhaled nitric oxide (FE(NO)) level for the diagnosis of pulmonary involvement due to IBD and to investigate any correlation between FE(NO) level and disease activity.
Methods: Thirty-three nonsmoker patients with IBD (25 ulcerative colitis [UC] and 8 Crohn's Disease [CD]) who were free of corticosteroid treatment and 25 healthy subjects as a control group were enrolled in this study. All patients with IBD were investigated for pulmonary involvement with medical history, physical examination, chest roentgenogram, oxygen saturation, blood eosinophil levels, pulmonary function tests (PFTs), high-resolution computed tomography (HRCT), and FE(NO) level.
Results: Pulmonary involvement was established in 15 patients (45.5%) with IBD. The FE(NO) level was higher in patients with pulmonary involvement than without pulmonary involvement and healthy controls independent from the pulmonary symptoms, eosinophil count, duration of disease, activity of disease, and surgery history (FE(NO): 32 +/- 20; 24 +/- 8; 14 +/- 8 ppb, respectively) (P < 0.05). In addition, diffusion capacity (DLCO) was found to be significantly lower in patients with CD compared with UC (P < 0.05).
Conclusions: This study showed that an increased FE(NO) level may be used for identifying patients with IBD who need further pulmonary evaluation.