Ironing It All Out: A Comprehensive Review of Iron Deficiency Anemia in Inflammatory Bowel Disease Patients

Iron deficiency anemia affects approximately 45% of patients with inflammatory bowel disease (IBD), negatively impacts the quality of life in this patient population, and significantly burdens our healthcare system. The pathogenesis of iron deficiency in IBD patients is multifactorial, including intestinal bleeding, malabsorption, and inadequate oral intake. Regular screening and diagnosis in these patients are imperative, and often patients have mixed iron deficiency anemia and anemia of chronic disease, especially in those with active inflammation. Iron may be replenished either orally or intravenously. While oral iron is safe, affordable, and easy to administer, patients often suffer from intolerable gastrointestinal side effects, and particularly in IBD patients, oral iron may increase inflammation and contribute to flares. Therefore, although it is substantially underused, intravenous (IV) iron is considered first-line treatment for patients with active disease, severe anemia, oral iron intolerance, and erythropoietin requirements. Several IV iron formulations are available, and iron sucrose and ferric carboxymaltose are the most frequently used and well studied in patients with IBD. However, iron isomaltoside could potentially become a popular choice among providers given its safety, efficacy, and convenience. Overall, screening, diagnosis, and treatment of iron deficiency anemia are important in patients with IBD. Individual patient characteristics, risks, and benefits, and advantages and disadvantages, should be considered when determining the best route and formulation for iron repletion.