When is iron supplementation indicated?

Indications for Iron Supplementation

Iron supplementation is indicated in all patients with iron deficiency anemia and should be initiated when serum ferritin is <30 μg/L in patients without inflammation or <100 μg/L in patients with inflammation. 1, 2

Diagnostic Criteria for Iron Deficiency

In Patients Without Inflammation

• Serum ferritin <30 μg/L 1, 2
• Transferrin saturation <16% 2
• Hemoglobin <12 g/dL in women or <13 g/dL in men 1, 2

In Patients With Inflammation

• Serum ferritin up to 100 μg/L may still indicate iron deficiency 1
• Transferrin saturation <20% with ferritin >100 μg/L indicates anemia of chronic disease 1
• Ferritin between 30-100 μg/L with low transferrin saturation suggests combined iron deficiency and anemia of chronic disease 1, 2

High-Risk Populations Requiring Screening

• Patients with inflammatory bowel disease (affects 13-90% of IBD patients) 3
• Pregnant women (up to 84% develop iron deficiency in third trimester) 3
• Menstruating women (38% have iron deficiency without anemia) 3
• Patients with chronic kidney disease (24-85%) 3
• Patients with heart failure (37-61%) 3
• Cancer patients (18-82%) 3
• Patients with gastrointestinal blood loss 2
• Patients with malabsorptive conditions (celiac disease, post-bariatric surgery) 2, 3

Treatment Approach

First-Line Treatment

• Oral iron supplementation for patients with:
  • Iron deficiency or mild anemia 1
  • Clinically inactive disease 1
  • No previous intolerance to oral iron 1
  • Typical dose: Ferrous sulfate 325 mg (65 mg elemental iron) once daily 2, 4

Intravenous Iron as First-Line Treatment

• Indicated for patients with:
  • Clinically active inflammatory bowel disease 1
  • Previous intolerance to oral iron 1
  • Hemoglobin <10 g/dL 1, 2
  • Need for erythropoiesis-stimulating agents 1
  • Malabsorptive conditions 2, 3
  • Ongoing blood loss 3
  • Second and third trimesters of pregnancy with severe anemia 3

Monitoring and Treatment Duration

• Check hemoglobin and ferritin after 8-10 weeks of therapy 1, 2
• Acceptable response: Increase in hemoglobin of at least 2 g/dL within 4 weeks 2
• Target ferritin level >30 μg/L 2
• Continue treatment for 3-6 months after normalization of hemoglobin to replenish iron stores 2

Optimizing Oral Iron Administration

• Consider alternate-day dosing to improve absorption and reduce side effects 5
• Administer iron in the morning rather than afternoon/evening 5
• Combine with vitamin C to enhance absorption 2
• If poor response after 4-8 weeks, consider:
  • Investigating underlying causes 2
  • Switching to intravenous iron 2

Common Pitfalls to Avoid

1. Failing to diagnose iron deficiency in patients with inflammation (ferritin up to 100 μg/L may still indicate deficiency) 1
2. Not investigating the cause of iron deficiency, especially in men and postmenopausal women (GI evaluation recommended) 2
3. Continuing daily high-dose iron despite poor tolerance (alternate-day dosing may be more effective) 5
4. Not screening high-risk populations such as IBD patients, pregnant women, and those with chronic diseases 3
5. Stopping supplementation too early before iron stores are replenished 2
6. Administering iron with foods that inhibit absorption (tea, coffee, dairy) 2
7. Not considering IV iron when oral iron is ineffective or contraindicated 1, 2

Iron supplementation is essential for improving quality of life, cognitive function, physical performance, and preventing complications such as developmental delays in children and adverse pregnancy outcomes 2, 3.