Study design: multicenter, prospective randomized non-inferiority study. Study population: Patients with inflammatory bowel disease on immunosuppressive medication with iron deficiency anemia, with increased inflammation parameters, but without an elevated ferritin (<100 μg/L).~Intervention: 152 patients will be randomized to a treatment group with either low dose oral iron or iv iron supplementation.~Main study endpoints: Normalization of Hb concentration (> 7.3 mmol/L (females) or > 8.0 mmol/L (males)) from baseline to week 12 in both oral and iv iron supplementation group.~Patients will receive either oral or intravenous iron therapy. Both therapies will be given according to existing guidelines. Participation to this trial will not increase the frequency of regular follow-up visits for patients. Blood for study measurements will be drawn simultaneously as blood for standard care tests. In addition, three questionnaires will be sent out regarding the patient's quality of life, disease activity, and productivity impairment. Iron therapy and biomaterial acquisition do not increase patients' risk because patients would have to undergo the same tests for standard IBD-care and receive iron therapy outside of the study. The study will be directly beneficial to participating patients because patients will undergo treatment for iron deficiency. The findings might help to develop guidelines for personalized iron therapy in the IBD population.
Rationale: Iron deficiency anemia is the most common systemic manifestation of Inflammatory Bowel Diseases (IBD)-Crohn's disease and ulcerative colitis. Iron deficiency with or without anemia poses a diagnostic and therapeutic challenge due to chronic gastrointestinal blood loss and the inflammatory nature of IBD. Oral iron supplementation in active disease states is controversial. Hepcidin levels can be considered as the sum effect of all regulatory processes. Studies suggested that iron stores and hypoxia reduce hepcidin levels even in an inflammatory state. This is also reflected by a study which demonstrated low levels of hepcidin in patients with ferritin levels under 30μg/ml, regardless of disease activity or type. Furthermore, studies show that immunosuppressive medication decrease the level of hepcidin. This raises the question: is oral iron a viable alternative for patients under immunosuppressive treatment for active IBD? Objective: The hypothesis is that patients with mild to moderate IBD activity on immunosuppressive medication, show the same level of Hb increase after 12 weeks after either oral or iv iron supplementation, while the price of oral iron supplementation is significantly lower.