Dave CV, Brittenham GM, Carson JL, Setoguchi S. Risks for Anaphylaxis With Intravenous Iron Formulations : A Retrospective Cohort Study.
Ann Intern Med 2022;
175:656-664. [PMID:
35344378 DOI:
10.7326/m21-4009]
[Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND
The risks for anaphylaxis among intravenous (IV) iron products currently in use have not been assessed.
OBJECTIVE
To compare risks for anaphylaxis among 5 IV iron products that are used frequently.
DESIGN
Retrospective cohort study using a target trial emulation framework.
SETTING
Medicare fee-for-service data with Part D coverage between July 2013 and December 2018.
PARTICIPANTS
Older adults receiving their first administration of IV iron.
MEASUREMENTS
The primary outcome was the occurrence of anaphylaxis within 1 day of IV iron administration, ascertained using a validated case definition. Analysis was adjusted for 40 baseline covariates using inverse probability of treatment weighting. The adjusted incidence rates (IRs) for anaphylaxis per 10 000 first administrations and odds ratios (ORs) were computed.
RESULTS
The adjusted IRs for anaphylaxis per 10 000 first administrations were 9.8 cases (95% CI, 6.2 to 15.3 cases) for iron dextran, 4.0 cases (CI, 2.5 to 6.6 cases) for ferumoxytol, 1.5 cases (CI, 0.3 to 6.6 cases) for ferric gluconate, 1.2 cases (CI, 0.6 to 2.5 cases) for iron sucrose, and 0.8 cases (CI, 0.3 to 2.6 cases) for ferric carboxymaltose. Using iron sucrose as the referent category, the adjusted ORs for anaphylaxis were 8.3 (CI, 3.5 to 19.8) for iron dextran and 3.4 (CI, 1.4 to 8.3) for ferumoxytol. When cohort entry was restricted to the period after withdrawal of high-molecular-weight iron dextran from the U.S. market in 2014, the risk for anaphylaxis associated with low-molecular-weight iron dextran (OR, 8.4 [CI, 2.8 to 24.7]) did not change appreciably. Anaphylactic reactions requiring hospitalizations were observed only among patients using iron dextran or ferumoxytol.
LIMITATION
Generalizability to non-Medicare populations.
CONCLUSION
The rates of anaphylaxis were very low with all IV iron products but were 3- to 8-fold greater for iron dextran and ferumoxytol than for iron sucrose.
PRIMARY FUNDING SOURCE
None.
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