Review of issues relating to iron and infection

Use of erythropoietin (EPO) therapy and iron supplementation has improved t he management of anemia in patients with end-stage renal disease (ESRD). As more patients receive supplemental iron, however, concerns are being raise d about a potential link between iron and infection. There is biologic plau sibility for this link, since iron is a growth factor for bacteria and cert ain host defense mechanisms are iron-sensitive. Animal models show that inj ection of iron leads to increased susceptibility to bacterial infection. In some studies, patients with high serum ferritin levels have reduced neutro phil function. However, these studies did not determine whether serum ferri tin levels were elevated because of increased iron stores or because of inf ection. If infection is present, it might cause both the elevated serum fer ritin levels and the neutrophil dysfunction. Several clinical studies have found an association between high serum ferritin levels and increased infec tious risk. In studies that control for important covariates such as use of catheters and previous infections, the infectious risk associated with iro n administration or elevated serum ferritin levels is reduced or eliminated . Collectively, these studies suggest that our current understanding of the relationship between iron and infection is incomplete and further Studies are needed. There is no reason to alter current iron treatment strategies b ased on this literature. (C) 1999 by the National Kidney Foundation, Inc.