[Diagnosis and treatment of iron deficiency anemia]

The causes of iron deficiency anemia include blood loss, increased demand, insufficient dietary intake, and disorders affecting iron absorption. In certain circumstances, atrophic gastritis, either autoimmune or due to Helicobacter pylori infection, may contribute. On very rare occasions, iron-refractory iron deficiency anemia can develop as a consequence of TMPRSS6 mutations. Iron deficiency anemia is diagnosed by identification of microcytic hypochromic anemia with low serum ferritin levels. In cases of chronic disorders such as chronic kidney disease, chronic heart failure, and chronic inflammatory disorders, the diagnosis may also incorporate transferrin saturation. Treatment of underlying diseases is recommended along with iron supplementation. While oral iron supplements are the first choice, intravenous iron may be considered when oral administration is impractical, iron absorption is impaired, or rapid iron replenishment is necessary. Recently, high-dose intravenous iron formulations became available in Japan, but their use requires caution due to potential risks of allergic reactions, hypophosphatemia/osteomalacia, iron overload, and vascular leakage. Notably, the benefits of high-dose intravenous iron for patients with heart failure and iron deficiency are recognized in the field of cardiology. This article provides an overview, incorporating recent developments in the field of iron deficiency anemia.