Anemia in inflammatory bowel disease

Anemia is a frequent extraenteric complication of inflammatory bowel disease (IBD, Crohn's disease and ulcerative colitis). A systematic review of the literature shows that the overall prevalence of anemia ranges from 8.8% to 73.7% but differs whether in a setting of Crohn's disease or ulcerative colitis. A disabling complication of IBD, anemia worsens the patient's general condition and quality of life, and increases hospitalization rates. Different factors, including vitamin B12 and folic acid deficiency, bone marrow suppression secondary to drug therapy, autoimmune hemolytic anemia and the coexistence of myelodysplastic syndromes are involved in the pathogenesis of anemia in IBD. The main types of anemia in IBD are iron deficiency anemia and anemia accompanying chronic diseases. Correct diagnostic definition of anemia is a fundamental step in guiding the choice of therapeutic options, since the co-presence of different pathogenetic factors may sometimes require a more complex treatment plan. A review of anemia in IBD, its pathogenetic features, epidemiology, diagnosis and therapy based on evidence from recent studies is the focus of this article.