Iron deficiency anemia in chronic kidney disease: Uncertainties and cautions

Anemia in chronic kidney disease is common and iron deficiency is an important cause. To repair iron-deficiency anemia, replacement of iron is needed. Iron can be replaced either by the oral route or by the intravenous route. In a meta-analysis, 5 of the 6 trials were short-term, 1 to 3 months, and compared to oral iron, the mean increase in hemoglobin with intravenous iron was only 0.31 g/dL. However, one of the studies included in this meta-analysis was 6 months long and had a mean decline in hemoglobin of 0.52 g/dL associated with intravenous iron administration. Given the short duration of most of the clinical trials comparing oral with intravenous administration of iron the long-term safety of these modes of administration of supplemental iron could not be assessed. Replacement of iron by the oral route is associated with mostly minor complications such as black stools, constipation, and abdominal discomfort. In contrast, intravenous administration of iron may lead to severe adverse events such as anaphylaxis and, as a more recent randomized trial has suggested, delayed complications such as infections and cardiovascular disease. Delayed complications of repeated intravenous iron use are difficult to recognize at an individual level therefore inpatients who have had recent cardiovascular events or are infected, intravenous iron should probably be avoided. Balancing safety and efficacy would require clinical judgment because 1 size may not fit all till we have better data to support the liberal use of parenteral iron.