Efficacy and safety of iron therapy in patients with chronic heart failure and iron deficiency: a systematic review and meta-analysis based on 15 randomised controlled trials

Trials studying iron administration in patients with chronic heart failure (CHF) and iron deficiency (ID) have sprung up these years but the results remain inconsistent. The aim of this meta-analysis was to comprehensively evaluate the efficacy and safety of iron therapy in patients with CHF and ID. A literature search was conducted across PubMed, Embase, Cochrane Library, OVID and Web of Science up to 31 July 2019 to search for randomised controlled trials (RCT) comparing iron therapy with placebo in CHF with ID, regardless of presence of anaemia. Published studies reporting data of any of the following outcomes were included: all-cause death, cardiovascular hospitalisation, adverse events, New York Heart Association (NYHA) functional class, left ventricular ejection fraction (LVEF), N-terminal pro b-type natriuretic peptide, peak oxygen consumption, 6 min walking test (6MWT) distance and quality of life (QoL) parameters. 15 RCTs with a total of 1627 patients (911 in iron therapy and 716 in control) were included. Iron therapy was demonstrated to reduce the risk of cardiovascular hospitalisation (OR 0.35, 95% CI 0.12 to 0.99, p=0.049), but was ineffective in reducing all-cause death (OR 0.59, 95% CI 0.33 to 1.06, p=0.078) or cardiovascular death (OR 0.80, 95% CI 0.39 to 1.63, p=0.540). Iron therapy resulted in a reduction in NYHA class (mean difference (MD) -0.73, 95% CI -0.99 to -0.47, p<0.001), an increase in LVEF (MD +4.35, 95% CI 0.69 to 8.00, p=0.020), 6MWT distance (MD +35.44, 95% CI 11.55 to 59.33, p=0.004) and an improvement in QoL: EQ-5D score (MD +4.07, 95% CI 0.84 to 7.31, p=0.014); Minnesota Living With Heart Failure Questionnaire score (MD -19.47, 95% CI -23.36 to -15.59, p<0.001) and Patients Global Assessment (PGA) scale (MD 0.71, 95% CI 0.32 to 1.10, p<0.001). There was no significant difference in adverse events or serious adverse events between iron treatment group and control group. Iron therapy reduces cardiovascular hospitalisation in patients with CHF with ID, and additionally improves cardiac function, exercise capacity and QoL in patients with CHF with ID and anaemia, without an increase of adverse events.