Comparative efficacy of intravenous and oral iron supplements for the treatment of iron deficiency in patients with heart failure: A network meta-analysis of randomized controlled trials

We aimed at comparing the efficacy of intravenous and oral iron supplementations for the treatment of iron deficiency (ID) in patients with heart failure (HF). We searched the PubMed, Cochrane, and Embase databases from inception to January 15, 2022. We included randomized controlled trials enrolling patients with HF who were treated for ID with intravenous iron supplements, oral iron supplements, or placebo. The primary outcomes were all-cause death, cardiovascular mortality, and hospitalization for heart failure. The secondary outcomes were evaluated through the six-minute walking test (6MWT) and the Kansas City Cardiomyopathy Questionnaire (KCCQ). The network meta-analysis included sixteen studies. Compared to placebo/control groups, intravenous iron supplements did not decrease all-cause death (0.69, 0.39–1.23) or cardiovascular mortality (0.89, 0.66–1.20). After 12 weeks, a reduced hospitalization for heart failure was associated with the administration of intravenous iron supplementations (0.58, 0.34–0.97). The most significant improvements regarding 6MWT (44.44, 6.10–82.79) and KCCQ (5.96, 3.19–8.73) were observed with intravenous iron supplements. Oral iron supplements reduced hospitalization for heart failure (0.36, 0.14–0.96) and all-cause death (0.34, 0.12–0.95), but did not influence the 6MWT (29.74, −47.36 to 106.83) and KCCQ (0.10, −10.95 to 11.15). Administering intravenous iron supplements for ID in patients with HF improves their exercise capacity and quality of life. In order to reduce hospitalizations for heart failure, the supplementation should be administered for more than 12 weeks. Although oral iron supplements did not improve exercise capacity and quality of life, they could reduce all-cause death and hospitalizations for heart failure.