Iron deficiency and anaemia in bariatric surgical patients: causes, diagnosis and proper management

Obesity-induced chronic inflammation leads to activation of the immune system that causes alterations of iron homeostasis including hypoferraemia, iron-restricted erythropoiesis, and finally mild-to-moderate anaemia. Thus, preoperative anaemia and iron deficiency are common among obese patients scheduled for bariatric surgery (BS). Assessment of patients should include a complete haematological and biochemical laboratory work-up, including measurement of iron stores, vitamin B12 and folate. In addition, gastrointestinal evaluation is recommended for most patients with iron-deficiency anaemia. On the other hand, BS is a long-lasting inflammatory stimulus in itself and entails a reduction of the gastric capacity and/or exclusion from the gastrointestinal tract which impair nutrients absorption, including dietary iron. Chronic gastrointestinal blood loss and iron-losingenteropathy may also contribute to iron deficiency after BS. Perioperative anaemia has been linked to increased postoperative morbidity and mortality and decreased quality of life after major surgery, whereas treatment of perioperative anaemia, and even haematinic deficiency without anaemia, has been shown to improve patient outcomes and quality of life. However, long-term follow-up data in regard to prevalence, severity, and causes of anaemia after BS are mostly absent. Iron supplements should be administered to patients after BS, but compliance with oral iron is no good. In addition, once iron deficiency has developed, it may prove refractory to oral treatment. In these situations, IV iron (which can circumvent the iron blockade at enterocytes and macrophages) has emerged as a safe and effective alternative for perioperative anaemia management. Monitoring should continue indefinitely even after the initial iron repletion and anaemia resolution, and maintenance IV iron treatment should be provided as required. New IV preparations, such ferric carboxymaltose, are safe, easy to use and up to 1000 mg can be given in a single session, thus providing an excellent tool to avoid or treat iron deficiency in this patient population.

Intravenous iron in inflammatory bowel disease

The prevalence of anemia across studies on patients with inflammatory bowel disease (IBD) is high (30%). Both iron deficiency (ID) and anemia of chronic disease contribute most to the development of anemia in IBD. The prevalence of ID is even higher (45%). Anemia and ID negatively impact the patient's quality of life. Therefore, together with an adequate control of disease activity, iron replacement therapy should start as soon as anemia or ID is detected to attain a normal hemoglobin (Hb) and iron status. Many patients will respond to oral iron, but compliance may be poor, whereas intravenous (i.v.) compounds are safe, provide a faster Hb increase and iron store repletion, and presents a lower rate of treatment discontinuation. Absolute indications for i.v. iron treatment should include severe anemia, intolerance or inappropriate response to oral iron, severe intestinal disease activity, or use of an erythropoietic stimulating agent. Four different products are principally used in clinical practice, which differ in their pharmacokinetic properties and safety profiles: iron gluconate and iron sucrose (lower single doses), and iron dextran and ferric carboxymaltose (higher single doses). After the initial resolution of anemia and the repletion of iron stores, the patient's hematological and iron parameters should be carefully and periodically monitored, and maintenance iron treatment should be provided as required. New i.v. preparations that allow for giving 1000-1500 mg in a single session, thus facilitating patient management, provide an excellent tool to prevent or treat anemia and ID in this patient population, which in turn avoids allogeneic blood transfusion and improves their quality of life.