Abstract
Treatment with erythropoiesis-stimulating agents (ESAs) enables the correction of anaemia in chronic kidney disease (CKD) patients, thus reducing its symptoms and complications. Not only is iron therapy aimed at correcting iron deficiency, but also it is an adjuvant therapy in CKD patients receiving ESAs. Iron stores in CKD patients may be near normal, but there may be insufficient immediately available iron to optimize ESA therapy. In this context, iron therapy significantly reduces ESA dose requirements. Erythropoiesis following ESA therapy may precipitate iron deficiency in association with increased platelet production. In the TREAT trial, the 'placebo group' did not receive a true 'placebo' since 46% of the patients had at least one dose of ESA and achieved progressively increased haemoglobin (Hb) values during follow-up against the common observation. The patients in the 'placebo' group were treated more frequently with intravenous iron than the darbepoetin group. Given that many patients were relatively iron deficient at baseline, iron administration was successful in many of them in obtaining and maintaining partial anaemia correction without the need for ESAs, thus underlining the great importance of iron supplementation in correcting anaemia. The upper safety limit for iron administered to patients in order to minimize, as much as possible, the ESA dose and the upper limit for ESA dosage for maintaining the target Hb range as suggested by the current guidelines are still open questions.