Risks for Anaphylaxis With Intravenous Iron Formulations : A Retrospective Cohort Study

Area of Science:

• Pharmacovigilance
• Clinical Therapeutics
• Immunology

Background:

• Anaphylaxis risks associated with intravenous (IV) iron products have not been thoroughly evaluated.
• Understanding these risks is crucial for patient safety in iron replacement therapy.

Purpose of the Study:

• To compare the anaphylaxis risks across five frequently used IV iron formulations.
• Identify specific IV iron products with potentially higher anaphylaxis rates.

Main Methods:

• Retrospective cohort study utilizing Medicare data (2013-2018) and a target trial emulation framework.
• Analyzed first-time IV iron administrations in older adults, adjusting for 40 covariates.
• Primary outcome: anaphylaxis within 1 day of IV iron administration, using a validated case definition.

Main Results:

• All IV iron products demonstrated very low anaphylaxis rates.
• Iron dextran and ferumoxytol exhibited 3- to 8-fold higher adjusted incidence rates of anaphylaxis compared to iron sucrose.
• Anaphylaxis requiring hospitalization was observed only with iron dextran and ferumoxytol use.

Conclusions:

• While overall anaphylaxis risk is low, significant differences exist among IV iron products.
• Iron dextran and ferumoxytol are associated with increased anaphylaxis risk relative to iron sucrose.
• Findings support careful consideration of IV iron product selection for minimizing anaphylaxis risk.