Prevalence and outcomes of anemia in inflammatory bowel disease: a systematic review of the literature.

The prevalence of anemia in patients with inflammatory bowel disease ranges from 8.8% to 73.7% depending on the patient subpopulation. Anemia, one of many extraintestinal complications of ulcerative colitis and Crohn disease, is generally defined as a hemoglobin value <120 g/L or hematocrit <0.4; severe anemia is defined as a hemoglobin level <100 g/L. Many patients have been shown to be intolerant of oral iron replacement therapy or their anemia was refractory to such supplementation. Correction of anemia through the administration of intravenous iron saccharate and/or supplemental erythropoietin has been shown to improve patient hematologic indices and quality of life. Future studies are needed to determine the type of patients at highest risk of developing severe anemia as well as the treatment interventions with the most beneficial effect.