Documented Adverse Reactions to Different Intravenous Iron Formulations in the Veterans Health Administration: A 10‐Year Retrospective Study

BACKGROUND: Intravenous (IV) iron is associated with a low risk of adverse drug reactions (ADR); however, the risk varies by formulation. METHODS: A 10-year retrospective cohort study of Veterans Health Administration data was conducted to detect the cumulative incidence of any documented ADR, potentially serious ADR, and anaphylaxis to five IV iron formulations. Patients with any exposure to each of the five IV iron formulations were identified and assessed for subsequent ADR documentation listed to the same IV iron formulation. RESULTS: A total of 133 588 patients were exposed to 162 457 unique IV iron formulations. The overall documented IV iron ADR cumulative incidence was 79 events per 10 000 (0.79%; 95% CI: 0.75%-0.84%). The potentially serious documented IV iron ADR cumulative incidence was 63 events per 10 000 (0.63%; 95% CI: 0.60%- 0.67%). The lowest cumulative incidence of documented ADR was associated with ferric carboxymaltose with 24 events per 10 000 (0.24%; 95% CI: 0.15%- 0.4%). Iron dextran was associated with the highest cumulative incidence of documented ADR with 189 events per 10 000 (1.89%; 95% CI: 1.74%- 2.05%). Iron dextran was also associated with the highest cumulative incidence of potentially serious ADR with 153 events per 10 000 (1.53%; 95% CI: 1.39%- 1.68%) and the highest cumulative incidence of documented anaphylaxis with 36 events per 10 000 (0.36%; 95% CI: 0.3%- 0.43%). CONCLUSIONS: The present study finds varying risk of documented potentially serious ADR and anaphylaxis between available IV iron formulations and aligns with previous data suggesting iron dextran is associated with a higher risk of serious ADR.