Intravenous iron in chronic kidney disease without anaemia but iron deficiency: A scoping review

Abstract

Iron deficiency (ID) is a prevalent complication of chronic kidney disease (CKD), often managed reactively when associated with anaemia. This scoping review evaluates the evidence supporting intravenous (IV) iron therapy in non-anaemic individuals with CKD and ID, focusing on safety, efficacy, and emerging therapeutic implications. Current diagnostic markers, including serum ferritin, transferrin saturation, and reticulocyte haemoglobin content, are reviewed alongside their limitations in the context of inflammation and variability. The pathophysiology of ID in CKD is explored, highlighting the roles of hepcidin, hypoxia-inducible factor pathways, and uraemic toxins. Comparative studies reveal that IV iron offers a more rapid correction of iron stores, improved compliance, and fewer gastrointestinal side effects compared to oral iron. Evidence from trials such as “iron and heart” and “iron and muscle” suggests potential benefits of IV iron on functional capacity and fatigue, though findings were statistically non-significant. Insights from heart failure trials support the safety and efficacy of IV iron in improving quality of life and reducing hospitalizations, with newer formulations like ferric derisomaltose demonstrating favourable safety profiles. This review underscores the need for standardized screening protocols for ID in CKD, even in the absence of anaemia, to facilitate earlier intervention. Future research should prioritise robust outcome measures, larger sample sizes, and person-specific treatment strategies to optimise dosing and administration frequency. Tailored approaches to IV iron therapy have the potential to significantly improve functional outcomes, quality of life, and long-term health in people with CKD.

Keywords: Iron; Chronic kidney disease; Cardiovascular; Disease; Glomerular filtration rate

Core Tip: Intravenous iron therapy can effectively address iron deficiency in individuals with chronic kidney disease who are non-dialysis-dependent and not anaemic, particularly when oral iron is insufficient. This review highlights the pathophysiology of iron deficiency in chronic kidney disease, the advantages of newer intravenous iron formulations, and the potential benefit of treatment in managing symptoms like restless legs syndrome. However, evidence on improvements in physical function remain uncertain, and more research is needed to refine treatment protocols.