Daily versus alternate-day oral iron in women with iron deficiency anemia: impact of dosing schedule and adherence on hemoglobin recovery.

INTRODUCTION: Iron deficiency anemia (IDA) is common among women of reproductive age and is frequently associated with abnormal uterine bleeding (AUB). Although oral iron is first-line therapy, the optimal dosing schedule remains uncertain. This study compared daily and alternate-day oral iron in real-world practice. MATERIALS AND METHODS: We conducted a prospective observational cohort study of women aged 18-70 years with confirmed IDA treated with oral ferrous sulfate at a tertiary referral center between January 2023 and June 2024. Patients received oral iron every 24 h or every 48 h according to physician prescription. AUB etiology was classified using the PALM-COEIN system. Outcomes included hemoglobin change, World Health Organization anemia severity, hemoglobin normalization (≥12 g/dL), adherence, adverse-event-related discontinuation, and intravenous iron escalation. RESULTS: A total of 171 women were included. Leiomyomas were the most frequent PALM-COEIN category (106 patients, 62.0%). Mean baseline hemoglobin was 9.02 ± 1.45 g/dL. At 6 weeks, mean hemoglobin was 10.91 ± 1.76 g/dL in the 24-h group and 11.26 ± 1.86 g/dL in the 48-h group (p = 0.255). At 3 months, final hemoglobin was available in 147 patients; mean values were 12.79 ± 1.68 g/dL and 12.68 ± 1.62 g/dL, respectively (p = 0.692). Hemoglobin normalization occurred in 75.2 and 71.7% of patients, respectively (p = 0.687). Adherence was high, and discontinuation due to adverse events was uncommon. Intravenous iron escalation was numerically more frequent with alternate-day therapy (26.8% vs. 13.9%; p = 0.056), although escalation decisions were based on clinical judgment without standardized criteria. CONCLUSION: Both regimens were associated with hematologic improvement. However, because allocation was non-randomized, baseline differences were present, and intravenous iron escalation was not based on standardized criteria, equivalence cannot be inferred. Oral iron dosing should be individualized.