SAGES Magazine

THE SOUTH AFRICAN GASTROENTEROLOGY REVIEW 2022 | VOLUME 20 | ISSUE 1 | 16 REVIEW Iron deficiency anaemia is one of the most common extraintenstinal manfestations in patients with IBD. Therefore, all IBD patients should be screened for the presence of anaemia 1 . The World Health Organisation defines anaemia as a haemoglobin (Hb) level of less than 13,0 g/dl in men and less than 12,0 g/dl and 11,0 g/dl in nonpregnant and pregnant women, respectively 2 . The anaemia prevalence rate in IBD ranges from 6 to 74% in the literature 3 , with the marked differences relating to study populations (in- versus out-patient), disease entities (Crohn’s disease versus ulcerative colitis) or the anaemia definition used 3 . Recent data has shown that up to 49% of Crohn’s disease patients and 39% of ulcerative colitis (UC) patients have had at least one episode of anaemia in the first 12 months after initial diagnosis 4 . Another study revealed that 32% of UC patients and 38% of Crohn’s patients had iron deficiency (ID) 5 . Although iron deficiency is the most common cause of anaemia in IBD, anaemia of chronic disease (inflammation) is also an important cause, especially in patients with chronic active disease 67 . Less frequently a vitamin deficiency (Vitamin B12 or folate) or drug therapy (sulfasalazine or thiopurine) may be the cause. Rarely, anaemia may be due to haemolysis, myelodysplastic syndrome, chronic renal insufficiency, aplasia (often drug-induced), inborn haemoglobinopathies or other disorders of erythropoiesis 6 . Symptoms of iron deficiency, with or without anaemia, include: chronic fatigue, headache, impaired cognitive function, dyspnoea, tachycardia, anorexia, nausea, increased susceptibility to infection, and motility disorders 6 . Screening for anaemia and iron deficiency in IBD is important. A full blood count (FBC), serum ferritin, transferrin saturation and C-reactive protein (CRP) should be performed every 6 to 12 months in patients in remission or with mild disease and every 3 months in patients with active disease. Patients at risk for vitamin B12 or folate deficiency (e.g. small bowel disease or extensive resection) or those with a macrocytosis in the absence of thiopurine use should have their serum vitamin B12 and folic acid levels measured at least annually. An anaemia workup should be initiated if the haemoglobin (Hb) is below normal (< 13 g/dl in men and < 12 g/dl in women). The minimum workup includes red blood cell indices such as red cell distribution width (RDW), mean corpuscular volume (MCV), reticulocyte count, differential blood cell count, serum ferritin, transferrin saturation (TSAT) and CRP concentration. A more extensive workup may then be indicated and includes vitamin B12, folic acid, haptoglobin (for haemolysis), the percentage of hypochromic red cells, reticulocyte haemoglobin (CHr), lactate dehydrogenase, soluble transferrin receptor, creatinine and urea. The diagnostic criteria for iron deficiency in patients with IBD depend on the level of inflammation. In patients without clinical, endoscopic or biochemical evidence of active disease, serum ferritin < 30 μg/l is an appropriate criterion. However, in the presence of inflammation, serum ferritin of up to 100 μg/l may be consistent with ID. A diagnosis of anaemia of chronic diseases can be made when there is biochemical (CRP increased) or clinical evidence of inflammation and the serum ferritin > 100 μg/l and the TSAT < 20%. If the serum ferritin level is between 30 and 100 μg/l, then a combination of true iron deficiency and anaemia of chronic diseases is likely. Iron supplementation is recommended in all IBD patients when iron deficiency anaemia is present 6 . The goal of iron supplementation is to normalise Hb levels and to replenish iron stores. i.v. iron should be considered as first-line treatment in patients with clinically active IBD, a previous intolerance to oral iron, a Hb < 10 g/dl and in patients treated with an erythropoiesis- stimulating agent. Studies have shown that i.v. iron provides a significantly higher and faster increase in the Hb levels and more patients normalise their Hb levels versus oral iron. Oral iron may be used in patients with IBD who have mild anaemia, whose disease is clinically Prof A Dignass Department of Medicine I, Agaplesion Markus Hospital, Frankfurt/Main, Germany Management of iron deficiency and anaemia in inflammatory bowel disease (IBD) Correspondence Prof A Dignass email: Axel.Dignass@fdk.info