Efficacy of Intravenous Iron in Patients with Heart Failure with Reduced Ejection Fraction and Iron Deficiency: A Systematic Review and Meta-Analysis of Randomized Control Trials

Abstract

Background: The European Society of Cardiology (ESC) provided a focused update to the 2021 Guideline for the Management of Heart Failure, now providing a 1A recommendation for intravenous iron in patients with heart failure with reduced ejection fraction (HFrEF) and iron deficiency (ID). However, the findings from randomized controlled trials (RCT) are mixed. This systematic review of RCTs aims to provide an update and synthesize the evidence addressing the association of intravenous iron with patient-based outcomes in patients with HFrEF and ID.

Methods: Any RCT evaluating the effect of intravenous iron in patients with HFrEF and ID was eligible for inclusion. A complete search of the EMBASE and PubMed databases was conducted from inception until 15 September 2023. The primary outcome was the composite of the quality of life (QoL) questionnaires, while the secondary outcomes included first heart failure (HF) hospitalizations and all-cause mortality. Data extraction was performed independently by two reviewers. Data were pooled using a random-effects model.

Results: Of the 1035 references, 15 RCTs enrolling 6649 patients were included in this study. Intravenous iron was associated with significant improvement in the composite of QoL (standardized mean difference - 1.36, 95% confidence interval [CI] - 2.24 to - 0.48; p = 0.002), a significant reduction in first HF hospitalizations (hazard ratio [HR] 0.73, 95% CI 0.56-0.95; p = 0.02), and with no change in all-cause mortality (HR 0.90, 95% CI 0.79-1.03; p = 0.12). The certainty of the evidence ranged from moderate to very low.

Conclusion: Intravenous iron is possibly associated with improved QoL and reduced HF hospitalizations, without impacting all-cause mortality. These findings not only support the use of intravenous iron in patients with HFrEF but also emphasize the need for well-designed and executed RCTs with granular outcome reporting and powered sufficiently to address the impact of intravenous iron on mortality in patients with HFrEF and ID.

Registration: PROSPERO identifier number CRD42023389.