Iron Deficiency Treatment

Introduction to Iron Deficiency

• Iron deficiency is a condition that can be absolute or functional, with absolute iron deficiency defined as serum ferritin <30 ng/mL in non-inflammatory conditions, or <100 ng/mL in patients with inflammation or cancer, as defined by the American Gastroenterological Association 1
• Functional iron deficiency is defined as TSAT <20% with ferritin 100-299 ng/mL, with a strength of evidence considered moderate to high 2
• Iron Deficiency Anemia (IDA) is characterized by serum ferritin <30 μg/L in patients without inflammation, as defined by the American Gastroenterological Association 3
• Anemia of Inflammation (AI) is characterized by serum ferritin up to 100 μg/L with transferrin saturation <20%, according to the American Gastroenterological Association 3

Intravenous Iron Administration

• The European Society for Clinical Nutrition and Metabolism (ESPEN) recommends ferric carboxymaltose as the best studied example for rapid administration of large single doses of IV iron, allowing infusion over 15 minutes 4
• The ESPEN guideline suggests that if more than basic amounts are required to correct iron deficiency, a single IV dose of whole-body iron replacement should be given, as 1 g of iron provided as a large single dose over 15 min using one of the recent carbohydrate products 4
• Different IV iron formulations have varying preparation, maximum single dose, and administration times, as summarized in the following table:

• The American College of Gastroenterology and European Crohn's and Colitis Organisation support the use of weight-based dosing for optimal repletion, and consider the Ganzoni formula or simplified dosing table for ferric carboxymaltose, with a recommended dosing schedule as follows:

Contraindications and Precautions

• Hypersensitivity to the active substance or any excipients is a contraindication, with a strength of evidence considered high 2
• Known serious hypersensitivity to other parenteral iron products is a contraindication, with a strength of evidence considered high 2
• Anemia not attributed to iron deficiency is a contraindication, with a strength of evidence considered high 2
• Evidence of iron overload or disturbances in iron utilization is a contraindication, with a strength of evidence considered high 2
• Active infection requires cautious use, with a recommended approach including monitoring for signs of infection and adjusting the treatment plan as needed 2
• Do not administer IV iron on the same day as anthracycline chemotherapy due to potential increased cardiotoxicity, with a strength of evidence considered high 6
• Avoid IV iron during periods of neutropenia as it may increase infection risk (RR 1.33), with a strength of evidence considered moderate to high 6

Monitoring and Follow-up

• A complete blood count with hemoglobin, hematocrit, MCV, MCH, iron studies, vitamin B12 and folate levels, inflammatory markers, and kidney function tests should be performed to assess the patient's condition, with a frequency of every 4 weeks until normalization 3
• Iron status should be re-evaluated 8-12 weeks after completion of therapy, with target parameters including hemoglobin ≥11-12 g/dL, ferritin >100 ng/mL, and transferrin saturation >20%, as recommended by the Gut guidelines and the European Journal of Heart Failure 7, 2
• Patients should be monitored for at least 30 minutes after infusion for hypersensitivity reactions, with a recommended monitoring plan including vital signs and clinical assessment 7, 2

Safety and Efficacy

• IV iron therapy has a favorable safety profile with a low risk of serious adverse reactions, and common side effects may include hypotension, flushing, and infusion site reactions, as supported by 8
• Common adverse effects of IV iron supplementation include hypersensitivity reactions, hypophosphatemia, infusion site reactions, transient hypotension, flushing, headache, and dizziness, with a strength of evidence considered moderate to high 3
• IV iron preparations provide significantly larger increases in ferritin (mean difference: 243 μg/L) and transferrin saturation (mean difference: 10.2%) compared to oral iron, with moderate increases in hemoglobin (mean difference: 0.9 g/dL), as supported by the American Society of Hematology 9
• Ferric carboxymaltose is considered the most cost-effective option, despite having a higher unit cost, as it requires fewer visits, with a cost-effectiveness analysis showing a significant reduction in healthcare costs 9