The Relevance of Vitamin and Iron Deficiency in Patients with Inflammatory Bowel Diseases in Patients of the Swiss IBD Cohort

Background and Aims: Vitamin and iron deficiencies are common in patients with inflammatory bowel disease (IBD) as a result of chronic intestinal inflammation, increase in demand, or dietary restrictions. Here, we assessed the frequency of complications in relation to deficiency of iron, folate acid, and vitamin B12 in patients enrolled in the nationwide Swiss Inflammatory Bowel Disease Cohort Study (SIBDCS). Methods: A total of 2666 patients were included in the study, 1558 with Crohn's disease (CD) and 1108 with ulcerative colitis (UC). Results: Iron deficiency anemia was detected in 19.6% of CD patients and 21.6% of UC patients. In CD patients low BMI and nonsmoker status were positively associated with anemia. In both CD and UC, malabsorption syndrome, defined as failure of the GI tract to absorb 1 or more substances from the diet, was found to be significantly associated with anemia (6.2% and 3.8%, respectively) and current steroid use (40% CD, 52.7% UC). In CD patients with ileal (31.7% vs 20%) and colonic (29.9% vs 25%) disease location folate deficiency was significantly higher than in patients with ileocolonic CD or upper GI involvement. In CD patients, vitamin B12 deficiency was associated with the onset of stenosis and intestinal surgery (42.9% vs 32.8% and 46% vs 33% for patients with versus without B12 deficiency). Conclusion: Our data indicate that due to frequent occurrence of deficiency states, regular monitoring and substitution of vitamins and iron are mandatory and may prevent long-term intestinal and extraintestinal complications in IBD patients.