Clinical Question

Is intravenous iron infusion superior to oral iron for avoiding blood transfusion in adults with iron deficiency anemia?

Evidence-Based Answer

No, intravenous iron administration does not reduce the need for blood transfusion compared with oral iron supplementation. (Strength of Recommendation [SOR]: A, multiple meta-analyses of randomized controlled trials [RCTs].) Compared with oral iron, intravenous iron has no effect on mortality. (SOR: B, multiple meta-analyses of RCTs.) Intravenous iron may increase the risk of infection compared with oral iron. (SOR: B, inconsistent evidence from meta-analyses of RCTs.)

Evidence Summary

A 2013 meta-analysis examined 72 RCTs (N = 10,605) comparing the effectiveness of intravenous iron vs. oral iron or no iron at preventing allogenic blood transfusions in anemic patients (hemoglobin [Hb] of 6.0 to 14.5 g per dL [60 to 145 g per L] with ferritin concentrations between 70 and 7,610 ng per mL [70 and 7,610 mcg per L]).¹ The participants were from a range of clinical specialties, including nephrology, obstetrics, surgery, oncology, cardiology, and gastroenterology. The most common intravenous preparation used was iron sucrose, 200 mg per dose for three to five doses or until replete. The oral iron preparations were not specified. There was no difference in the need for blood transfusion between intravenous iron and oral iron (14 studies; n = 2,263; relative risk [RR] = 0.82; 95% CI, 0.67 to 1.00). Intravenous iron was associated with an increased risk of infection (12 studies; n = 2,622; RR = 1.63; 95% CI, 1.16 to 2.29). Compared with oral or no iron, intravenous iron had no significant impact on mortality (20 studies; n not given; RR = 1.1; 95% CI, 0.8 to 1.5) or adverse effects (19 studies; n not given; RR = 1.1; 95% CI, 0.9 to 1.2). There was a high risk of bias because most studies were not blinded and study heterogeneity was significant.