Real-World Use of Intravenous Iron Therapy and Associated Clinical Outcomes in Patients With Heart Failure and Iron Deficiency

BACKGROUND: Intravenous (IV) iron supplementation is an important strategy for correcting iron deficiency in patients with heart failure with reduced ejection fraction (HFrEF). Despite guideline recommendations, real-world implementation remains inconsistent. OBJECTIVE: This study aimed to evaluate the real-world impact of IV iron therapy on clinical outcomes in patients with HFrEF and iron deficiency. METHODS: This retrospective cohort study included adult patients with HFrEF and iron deficiency, who were admitted between January 2022 and May 2024 and received IV iron during hospitalization. Clinical outcomes included all-cause mortality and rehospitalization within 12 months of discharge and were analyzed using Kaplan-Meier survival curves. Changes in laboratory values from baseline to 12 months were compared using paired t-tests or Wilcoxon signed-rank tests. RESULTS: Among 124 patients, death or rehospitalization occurred in 81 (65%), including 14 (11%) deaths, and among 119 discharged alive, 75 (63%) were rehospitalized within 12 months. Mean hemoglobin increased by 1.1 g/dL (95% confidence interval [CI] = 0.5 to 1.7; n = 46), median ferritin by 44 ng/mL (interquartile range [IQR] = 8.4-372; n = 23), transferrin saturation by 4% (IQR = 0-13; n = 22), and left ventricular ejection fraction (LVEF) by 3% (95% CI = -2 to 7; n = 33). CONCLUSION AND RELEVANCE: Among patients with HFrEF and iron deficiency who received IV iron during hospitalization, improvements in anemia and iron parameters and modest increases in LVEF were observed, while rehospitalization remained common. Real-world practice was characterized by lower cumulative dosing and barriers to outpatient continuation of IV iron therapy, which may have attenuated clinical benefit. Further research should define optimal dosing, improve outpatient delivery, and clarify the role of oral iron when IV iron is unavailable or not tolerated.