Short-term benefits and risks of intravenous iron: a systematic review and meta-analysis

Intravenous (IV) iron may correct anemia more efficiently than oral iron, but it has been associated with allergic and hemodynamic reactions, and it may increase the risks of infectious complications. The objective of this systematic review and meta-analysis was to clarify these controversial issues.

Studies evaluating the use of IV iron compared to enteral or no iron with outcomes within 2 months of treatment initiation were identified. Only randomized controlled trials were included. When a meta-analysis was possible, studies were combined with the Review Manager of the Cochrane Collaboration Group 2003. Statistics were calculated as standardized mean differences (SMDs), with a random-effect model.

Thirteen studies met inclusion criteria. Meta-analysis revealed a significant increase in the reticulocyte count (SMD, 0.70; 95% confidence interval [CI], 0.10-1.29; p = 0.02) and in ferritin levels (SMD, 1.18; 95% CI, 0.69-1.68; p = 0.00001), but it also showed that in such a short period of time, IV iron does not correct hemoglobin (Hb)-hematocrit (Hct) better than enteral or no iron. In a sensitivity analysis, however, the increase in Hb-Hct became significant in the nondextran group (SMD, 0.27; 95% CI, 0.04-0.51; p = 0.02). No increase in transferrin saturation was observed. Meta-analysis of the allergic and hemodynamic reactions was not possible as most studies did not clearly describe these outcomes.

Our results suggest that treatment with nondextran IV iron may benefit a wide variety of patients. Randomized controlled studies are definitively needed to further evaluate the usefulness and safety of IV iron.