Anemia in inflammatory bowel disease-A comprehensive review

Anemia is a frequent complication in inflammatory bowel disease (IBD) patients. The etiology is multifactorial, with iron deficiency and anemia of chronic disease being the main reasons. Other causes include vitamin B₁₂ and folate deficiency, hemolytic anemia and medications such as azathioprine and sulfasalazine. Apart from physical symptoms, it is associated with several negative outcomes, including poor quality of life, increased risk of hospital admission, increased risk of surgery and higher treatment costs. Diagnostic evaluation aims to identify the underlying cause and severity to determine the appropriate therapeutic strategy. Investigations include a complete blood count, iron indices, inflammatory markers and vitamin B₁₂ and folate levels. Patients with iron deficiency need adequate replacement therapy to improve hemoglobin and replenish iron stores. Those with moderate to severe anemia and/or active disease need intravenous iron, while mild anemia can be treated with oral iron. Multiple parenteral iron formulations are available which differ in dose and frequency of administration. Traditional oral iron supplements are available in ferrous forms, which, although effective, are associated with gastrointestinal side effects. Newer oral iron formulations have helped reduce these adverse effects but are expensive. Anemia of chronic disease is mainly driven by the effects of inflammatory mediators on iron metabolism and erythropoiesis and treatment requires control of disease activity. Relapse of anemia after therapy is frequent; hence, patients need to be closely followed up for early detection and appropriate management. Significant advances have been made in understanding the pathophysiology of anemia in IBD and better and safer iron formulations are available. However, a significant proportion of IBD patients with anemia go undetected or untreated and there is a need for improved recognition and better management practices. This review discusses various aspects of anemia in IBD and the current approach to diagnosis and management.