Efficacy and tolerability of oral iron therapy in inflammatory bowel disease: a prospective, comparative trial

In patients with inflammatory bowel disease, oral iron is anecdotally reported to be less effective and less well tolerated than in those without inflammatory bowel disease, and to increase disease activity.

To study prospectively the effects of oral iron in patients with and without inflammatory bowel disease.

Patients with ulcerative colitis, Crohn's disease and non-inflammatory bowel disease controls, all with iron deficiency anaemia, were assessed with symptom diaries, a quality of life questionnaire (Inflammatory Bowel Disease Questionnaire; inflammatory bowel disease patients only) and blood tests to measure iron repletion, disease activity and antioxidant capacity before and after starting 4 weeks of oral iron. In patients with ulcerative colitis, sigmoidoscopic scoring and rectal biopsies for reactive oxygen metabolite production were performed before and after iron therapy.

All groups showed increases in haemoglobin and ferritin. Iron intolerance occurred in about a quarter of patients in each group. Two of 33 (6%) of inflammatory bowel disease patients had a relapse during treatment. Symptoms worsened in ulcerative colitis, but not in Crohn's disease or non-inflammatory bowel disease patients; Inflammatory Bowel Disease Questionnaire scores improved in ulcerative colitis. Laboratory markers of disease activity, sigmoidoscopic scores, histological scores, antioxidant capacity levels and reactive oxygen metabolite production did not change.

Oral iron is equally efficacious and well tolerated in inflammatory bowel disease and non-inflammatory bowel disease patients. A tiny minority of inflammatory bowel disease patients relapse in association with use of oral iron therapy.