OBJECTIVES: The reported prevalence of iron deficiency anemia (IDA) varies widely but estimates suggest that 3% of men and 8% of women have IDA in the UK. Parenteral iron is indicated for patients intolerant or unresponsive to oral iron, or requiring rapid iron replenishment. This study evaluated differences in the cost of treating these patients with iron isomaltoside (Monofer; IIM) relative to other intravenous iron formulations. METHODS: A budget impact model was developed to evaluate the cost of using IIM relative to ferric carboxymaltose (Ferinject; FCM), low molecular weight iron dextran (Cosmofer; LMWID) and iron sucrose (Venofer; IS) in patients with IDA. To establish iron need, iron deficits were modeled using a simplified dosing table. The base case analysis was conducted over 1 year in patients with IDA with mean bodyweight of 82.4 kg (standard deviation [SD] 22.5 kg) and hemoglobin levels of 9.99 g/dL (SD 1.03 g/dL) based on an analysis of patient characteristics in IDA trials. Costs were modeled using UK healthcare resource groups. RESULTS: Using IIM required 1.34 infusions to correct the mean iron deficit, compared with 1.34, 1.77, and 7.74 with LMWID, FCM, and IS, respectively. Patients using IIM required multiple infusions in 34.6% of cases, compared with 34.6%, 77.2% and 99.8% of patients with LMWID, FCM and IS, respectively. Total costs were estimated to be GBP 451 per patient with IIM or LMWID, relative to GBP 594 with FCM (saving GBP 143 or 24.0% per patient) or GBP 2,600 with IS (saving GBP 2,148 or 82.6% per patient). CONCLUSIONS: Using IIM in place of FCM or IS resulted in a marked reduction in the number of infusions required to correct iron deficits in patients with IDA. The reduction in infusions was accompanied by substantial reductions in cost relative to FCM and IS over 1 year.