Intravenous Iron in Patients with Heart Failure and Iron Deficiency: An Updated Meta-Analysis

Abstract

Aims
For patients with heart failure (HF) and iron deficiency (ID), randomized trials suggest that intravenous (IV) iron reduces hospitalizations for heart failure (HHF), but uncertainty exists about the effects in subgroups and the impact on mortality. We conducted a meta-analysis of randomized trials investigating the effect of IV iron on clinical outcomes in patients with HF.


Methods and results
We identified randomized trials published between 1 January 2000 and 5 November 2022 investigating the effect of IV iron versus standard care/placebo in patients with HF and ID in any clinical setting, regardless of HF phenotype. Trials of oral iron or not in English were not included. The main outcomes of interest were a composite of HHF and cardiovascular death (CVD), on HHF alone and on cardiovascular and all-cause mortality. Ten trials were identified with 3373 participants, of whom 1759 were assigned to IV iron. IV iron reduced the composite of recurrent HHF and CVD (rate ratio 0.75, 95% confidence interval [CI] 0.61–0.93; p < 0.01) and first HHF or CVD (odds ratio [OR] 0.72, 95% CI 0.53–0.99; p = 0.04). Effects on cardiovascular (OR 0.86, 95% CI 0.70–1.05; p = 0.14) and all-cause mortality (OR 0.93, 95% CI 0.78–1.12; p = 0.47) were inconclusive. Results were similar in analyses confined to the first year of follow-up, which was less disrupted by the COVID-19 pandemic. Subgroup analyses found little evidence of heterogeneity for the effect on the primary endpoint, although patients with transferrin saturation <20% (OR 0.67, 95% CI 0.49–0.92) may have benefited more than those with values ≥20% (OR 0.99, 95% CI 0.74–1.30) (heterogeneity p = 0.07).


Conclusion
In patients with HF and ID, this meta-analysis suggests that IV iron reduces the risk of HHF but whether this is associated with a reduction in cardiovascular or all-cause mortality remains inconclusive.