What iron supplementation is recommended for patients with iron deficiency anemia?

Iron Supplementation for Iron Deficiency Anemia

For patients with iron deficiency anemia, oral iron supplementation with ferrous sulfate 200 mg three times daily is recommended as first-line treatment for most patients, while intravenous iron should be used for those with clinically active inflammatory conditions, previous intolerance to oral iron, hemoglobin below 10 g/dL, or those requiring erythropoiesis-stimulating agents. 1

Diagnosis of Iron Deficiency Anemia

• Iron deficiency anemia is diagnosed by low hemoglobin levels with evidence of iron deficiency, typically indicated by serum ferritin <30 μg/L in patients without inflammation 1
• In the presence of inflammation (elevated CRP), serum ferritin up to 100 μg/L may still be consistent with iron deficiency 1
• For laboratory screening, complete blood count, serum ferritin, and C-reactive protein should be used 1
• Diagnostic criteria for anemia of chronic disease are serum ferritin >100 μg/L and transferrin saturation <20% 1

Oral Iron Supplementation

First-line Treatment

• Oral iron should be considered first-line treatment for patients with:
  • Mild anemia 1
  • Clinically inactive disease 1
  • No previous intolerance to oral iron 1

Recommended Formulations and Dosing

• Ferrous sulfate 200 mg three times daily is the most common and cost-effective option 1
• Alternative formulations with similar effectiveness include:
  • Ferrous gluconate 1
  • Ferrous fumarate 1
• Liquid preparations may be better tolerated when tablets are not 1
• Adding ascorbic acid (vitamin C) enhances iron absorption and should be considered when response is poor 1

Duration of Treatment

• Iron supplementation should be continued for three months after correction of anemia to replenish iron stores 1
• An increase in hemoglobin of at least 2 g/dL within 4 weeks of treatment is considered an acceptable response 1
• If this response is not achieved, consider poor compliance, misdiagnosis, continued blood loss, or malabsorption 1

Intravenous Iron Supplementation

Indications for IV Iron

• Intravenous iron should be considered first-line treatment for patients with:
  • Clinically active inflammatory bowel disease 1
  • Previous intolerance to at least two oral iron preparations 1
  • Hemoglobin below 10 g/dL 1
  • Need for erythropoiesis-stimulating agents 1
  • Conditions with impaired iron absorption (bariatric surgery, celiac disease) 1
  • Non-compliance with oral therapy 1

IV Iron Formulations

• IV iron formulations that can replace iron deficits with 1-2 infusions are preferred over those requiring multiple infusions 1
• Ferric carboxymaltose has shown better efficacy and compliance compared to iron sucrose in clinical trials 1
• All IV iron formulations have similar risk profiles, with true anaphylaxis being very rare 1

Special Populations

Inflammatory Bowel Disease

• In IBD patients, anemia is the most frequent extraintestinal manifestation 1
• Active inflammation should be treated effectively to enhance iron absorption or reduce iron depletion 1
• For patients in remission, iron parameters should be measured every 6-12 months 1
• For patients with active disease, measurements should be performed at least every 3 months 1

Portal Hypertensive Gastropathy

• Oral iron supplements should initially be used to replenish iron stores 1
• Intravenous iron therapy should be used in patients with ongoing bleeding who don't respond to oral iron therapy 1

Celiac Disease

• Ensure adherence to a gluten-free diet to improve iron absorption 1
• Consider oral iron supplementation based on severity of iron deficiency and patient tolerance 1
• Use intravenous iron therapy if iron stores do not improve with oral supplementation 1

Follow-up and Monitoring

• Once hemoglobin normalizes, monitor hemoglobin concentration and red cell indices at three-month intervals for one year, then after a further year 1
• Additional oral iron should be given if hemoglobin or MCV falls below normal 1
• Further investigation is only necessary if hemoglobin and MCV cannot be maintained with iron supplementation 1

Common Pitfalls and Caveats

• Parenteral iron treatment can be painful (when given intramuscularly), expensive, and may cause infusion reactions 1
• The rise in hemoglobin with IV iron is not necessarily quicker than with oral preparations 1
• Poor compliance, particularly in adolescents, is common with iron supplements; patient education about the rationale is important 1
• Many serum values of micronutrients are affected by inflammation (ferritin increases, while folate, selenium, and zinc decrease) 1
• Oral iron may cause gastrointestinal side effects that reduce compliance; a liquid preparation may be better tolerated 1, 2