In this interesting paper, the authors performed a meta-analysis of 28 studies (2098 participants; up to 2010) to determine the benefits and harms of intravenous (IV) iron supplementation compared with oral iron for anemia in adults and children with chronic kidney disease (CKD). The quality of the evidence was classified according to the GRADE methodology as moderate or low. They identified evidence indicating that, compared to oral iron therapy, IV iron therapy increased serum ferritin (moderate), transferrin saturation (moderate) and reticulocyte hemoglobin content (moderate), reduced erythropoiesis-stimulating agent (ESA) dose requirements (low) and to provided a small but significant increase in hemoglobin (moderate). Mortality and cardiovascular morbidity did not differ significantly but were reported in few studies.

These data support the current practice of administering IV iron to in-center hemodialysis patients to increase iron stores and, probably, to reduce both the ESA dose required and its cost. However, the studies included did not provide sufficient evidence on patient-centered outcomes, including adverse effects, to determine if the benefits exceed harm for all patients with CKD.

In summary, there still exist areas of uncertainty regarding the use of IV iron in CKD patients and further large randomized studies with standardized doses of oral and IV iron (to reduce heterogeneity) and longer follow-up periods are required. These studies should focus on patient-centered outcomes (mortality, morbidity, hospitalizations, kidney function and time to start dialysis, quality of life and patient inconvenience) and costs, rather than on hematological parameters, to determine which patients would benefit from IV iron, particularly in non-dialysis patients.

– Manuel Muñoz