How do you treat a patient with low iron saturation?

Treatment of Low Iron Saturation

For patients with low iron saturation, oral iron supplementation should be initiated as first-line therapy with ferrous sulfate 200 mg three times daily, followed by intravenous iron therapy if oral treatment fails due to intolerance, malabsorption, or inadequate response. 1

Diagnosis Confirmation

Before initiating treatment, confirm iron deficiency with:

• Transferrin saturation <16% (key indicator of iron deficiency)
• Serum ferritin <30 μg/L (<45 ng/mL)
• Consider hemoglobin levels (<12 g/dL in women, <13 g/dL in men) 1

In inflammatory conditions, ferritin may be falsely elevated as an acute phase reactant, so use a higher cutoff value (<100 μg/L) and focus on transferrin saturation 1.

Treatment Algorithm

Step 1: Oral Iron Therapy

• First choice: Ferrous sulfate 200 mg three times daily (provides 65 mg elemental iron per tablet) 1
• Alternatives if ferrous sulfate not tolerated:
  • Ferrous gluconate 300 mg tablet (37 mg elemental iron)
  • Ferrous fumarate 210 mg tablet (69 mg elemental iron)
  • Ferric maltol 30 mg tablet (30 mg elemental iron) - better tolerated but more expensive 1

Administration tips:

• Take on empty stomach for best absorption
• May take with food if GI side effects occur (though reduces absorption)
• Consider alternate-day dosing if daily dosing causes side effects 1

Step 2: Monitoring Response

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment
• Continue therapy for 3 months after hemoglobin normalizes to replenish iron stores 1
• Monitor ferritin and transferrin saturation

Step 3: Consider IV Iron if:

• Intolerance to oral iron (significant GI side effects)
• No improvement in iron parameters within 2 weeks of oral therapy
• Severe anemia (hemoglobin <10 g/dL)
• Pronounced inflammatory disease activity
• Conditions with impaired iron absorption 2, 1

IV Iron Administration

For patients requiring IV iron, iron sucrose (Venofer) is a commonly used option:

• Non-dialysis dependent CKD: 200 mg undiluted as slow IV injection (2-5 minutes) or infusion (15 minutes) on 5 different occasions over 14 days 3
• Other indications: Dosing typically based on calculated iron deficit
• IV iron formulations that can replace iron deficits with 1-2 infusions are preferred 1

Special Considerations

• Inflammatory conditions: In patients with chronic inflammation, functional iron deficiency may occur despite normal iron stores. Consider IV iron if oral therapy fails 1
• Gastrointestinal side effects: Common with oral iron (constipation, diarrhea, nausea). Manage by taking iron with food, switching formulations, reducing dose, or using alternate-day dosing 1
• Blood transfusions: Should be restricted to special clinical situations such as acute severe anemia with hemodynamic instability 2
• Erythropoietic therapy: Consider when anemia doesn't improve despite IV iron therapy and control of inflammation. Should be combined with IV iron supplementation 2

Underlying Cause Investigation

While treating iron deficiency, investigate potential underlying causes:

• For men and postmenopausal women: Consider gastrointestinal endoscopy to rule out bleeding sources 4
• For premenopausal women: Heavy menstrual bleeding is a common cause
• Consider malabsorption disorders, dietary insufficiency, and chronic blood loss 1

Iron deficiency is the most common nutritional disorder worldwide, and proper treatment is essential to prevent complications including fatigue, reduced work capacity, impaired cognitive performance, and in severe cases, heart failure and developmental delays 1, 5.