A single 1 g dose of intravenous iron is sufficient treatment for most patients with iron deficiency anaemia, a New Zealand study has shown.

The review of 194 adult outpatients who received either 1 g of ferric carboxymaltose or iron polymaltose found the mean haemoglobin improvement after treatment was 24.7 g/L.

Patients were mostly female (81%) with a mean age of 38.8 years – reflecting the most common causes of anaemia which were menorrhagia and inflammatory bowel disease.

Pre and post-infusion blood tests also showed mean ferritin levels improved by an increment of 119.5 mcg/L with treatment.

Only five patients overall met the Hb <100 g/L criteria for a subsequent iron infusion.

“These patients were all at high risk of recurrent iron loss due to inflammatory bowel disease, severe menorrhagia, or recurrent gastrointestinal bleeding,” the study said.

Writing in the Internal Medicine Journal, the researchers said iron administration protocols and guidelines varied worldwide and there was uncertainty about appropriate dosing.

“Using a standard 1 g dose avoids uncertainty about which dose to choose, and avoids the complexity and errors associated with calculating doses.”

They said given its few adverse effects and rapid delivery, ferric carboxymaltose was ‘an appealing option’ especially for outpatient and community services.

They also noted evidence from an Australian study that most patients (86%) don’t return for recommended second doses anyway.

“Our results give reassurance that a single 1 g dose (and one visit) will be sufficient for most people.”

“Benefits include improved patient convenience and safety, reduced costs, and greater ability to treat in community settings.”

However they recommended that patients at high risk of anaemia recurrence, such as those with inflammatory bowel disease, should be carefully monitored via repeat testing for haemoglobin and ferritin 5–7 weeks after infusion.