The Relationship between Airway Resistance and Pulmonary Volumes in Active Phase of Ulcerative Colitis and Crohn's Disease

Inflammatory bowel disease (IBD) including ulcerative colitis (UC) and Crohn's disease (CD), as an autoimmune disorder, is associated with chronic relapsing inflammation of intestine. UC and CD are associated with gastrointestinal and extra-intestinal symptoms, which may vary in severity of clinical presentation. This study was designed to evaluate airway resistance and pulmonary volumes and capacities in the active phase of UC and CD. Patients who had IBD and referred to Shahid Modarres Hospital from February 2016 to December 2017 were assessed for enrollment in our study. Diagnosis of Crohn's disease or ulcerative colitis was confirmed by colonoscopic and pathological evaluations. Pulmonary respiratory parameters including first second of forced expiration (FEV1), forced vital capacity (FVC), residual volume (RV), total lung capacity (TLC), forced expiratory flow between 25% and 75% (FEF25-75%), and airway resistance were measured by plethysmography in the first days of admission in patients with stable IBD and also immediately after an initial stabilization of the vital signs in patients with unstable IBD. Data were analyzed using SPSS software (v.21. IBM Inc. IL). P value less than 0.05 was considered as statistically significant. Of 75 patients with IBD, 65 had UC and 10 had CD. The mean ages of the patients with UC and CD were 37.81 ± 13.31 and 34.20 ± 8.53 years, respectively. Of all the participants, approximately 54.7% and 45.3% of the patients were male and female, respectively. The duration of disease for patients with UC and CD was 43.09 ± 45.86 and 44.40 ± 15.45 months, respectively. Based on the Pearson correlation analysis, there were significant associations between FEV1, TLC, and FEF25-75% with the duration of UC and also between FEV1, RV, and airway resistance with the duration of CD. In patients with CD but not in the patients with UC, there were statistical relationships between FEV1, FVC, FEV1/FVC, RV, RV/TLC, FEF25-75% and increased airway resistance with severity and activation of IBD. According to our findings, pulmonary involvements were found often in patients with IBD with and without the presence of clinical pulmonary symptoms. The duration and also activation and severity of IBD can be associated with increased risk for pulmonary involvements.