brand logo

Am Fam Physician. 2022;106(2):191-192

Related Letter to the Editor: Intravenous Iron Replacement for Iron Deficiency Anemia

Author disclosure: No relevant financial relationships.

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.

Already a member/subscriber?  Log In


From $165
  • Immediate, unlimited access to all AFP content
  • More than 130 CME credits/year
  • AAFP app access
  • Print delivery available

Issue Access

  • Immediate, unlimited access to this issue's content
  • CME credits
  • AAFP app access
  • Print delivery available
Purchase Access:  Learn More

Clinical Inquiries provides answers to questions submitted by practicing family physicians to the Family Physicians Inquiries Network (FPIN). Members of the network select questions based on their relevance to family medicine. Answers are drawn from an approved set of evidence-based resources and undergo peer review. The strength of recommendations and the level of evidence for individual studies are rated using criteria developed by the Evidence-Based Medicine Working Group (

The complete database of evidence-based questions and answers is copyrighted by FPIN. If interested in submitting questions or writing answers for this series, go to or email:

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

A collection of FPIN’s Clinical Inquiries published in AFP is available at

Continue Reading

More in AFP

More in Pubmed

Copyright © 2022 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.