A Prospective Interventional Study to Evaluate the Effect of Hypoxia on Healthy Volunteers and Patients With Inflammatory Bowel Disease: The Altitude Inflammatory Bowel Disease Study

Introduction: Retrospective data suggest association of high-altitude exposure and inflammatory bowel disease flares. Knowledge about underlying pathogenesis remains limited. Methods: This prospective interventional trial evaluated the effect of 3 hours hypobaric low-pressure chamber exposure on 11 patients with Crohn's disease (CD), 9 with ulcerative colitis (UC), and 10 controls. Results: Proportion of patients with clinical and endoscopic activity did not increase. However, 33.3% of patients with UC experienced a flare. More patients had calprotectin-based activity (>100 μg/g) after the intervention (26.7 vs 63.3%, P = 0.013). Transient changes in certain bacterial strains were seen in controls and patients with UC. Discussion: Low-pressure chamber exposure, although the primary outcome was not met, led to a flare in a third of patients with UC, with changes in calprotectin levels and specific bacterial strains ( Clinicaltrials.gov number, NCT02849821).