Impact of Iron Supplementation on Clinical Outcomes in Iron-Deficient Heart Failure Patients: A Retrospective Cohort Study in Oman

Objective: The prevalence and clinical impact of iron deficiency (ID) in patients with heart failure (HF) in Oman remain insufficiently characterized. This study aimed to evaluate the prevalence of ID and its association with clinical outcomes, as well as to assess the impact of iron supplementation on hospitalization and mortality among HF patients. Methods: A retrospective observational cohort study included adult patients (≥18 years) with HF who had ≥2 iron profiles; patients with end-stage renal disease were excluded. ID was defined using American Heart Association (AHA) and European Society of Cardiology (ESC) criteria. Results: Of 2246 patients screened, 211 met inclusion criteria (57.8% female; mean age 70 ± 12.7 years). ID prevalence was 68.3% (AHA) and 71.1% (ESC), with ESC criteria detecting more biochemical deficiencies. ID was associated with higher all-cause and HF-related readmissions (p < 0.01), longer length of stay (p = 0.045), and more atrial fibrillation (AF) (p < 0.01). All-cause mortality was similar, although the composite of mortality and readmission was slightly higher with ID (p = 0.052). Iron supplementation significantly increased ferritin (+32 ng/mL) and transferrin saturation (+2.8%) (p < 0.01) and was linked to fewer strokes (p = 0.049), with no major differences in other outcomes. Conclusions: The study found that ID was highly prevalent; however, systematic screening was not routinely practiced, which largely led to delayed initiation of appropriate management. Routine ESC-guided ID screening and management are recommended. However, given the retrospective, non-randomized study design, these findings should not be interpreted as evidence of a causal treatment effect and are likely influenced by confounding by indication. Prospective randomized studies are needed to confirm these observations.