How to manage an elderly gentleman with anemia, on ferrous sulfate, with mild iron deficiency?

Management of Iron Deficiency Anemia in an Elderly Patient with Inadequate Response to Current Therapy

This patient requires an immediate increase in oral iron dosing from once daily to ferrous sulfate 200 mg three times daily, plus addition of vitamin C 500 mg with each dose, and investigation of the underlying cause of iron deficiency. 1

Critical Assessment of Current Therapy

The patient's laboratory values reveal severe functional iron deficiency despite being on ferrous sulfate:

• Iron saturation of 23% (should be >20%) indicates borderline iron availability 2
• Ferritin of 290 ng/mL is elevated, suggesting either inflammation or iron sequestration rather than true iron repletion 2
• Hemoglobin of 9.0 g/dL represents significant anemia requiring aggressive treatment 1

The once-daily dosing is inadequate for this degree of anemia. 1

Recommended Treatment Algorithm

Immediate Medication Adjustment

Increase to ferrous sulfate 200 mg three times daily (providing 195 mg elemental iron per day), which is the evidence-based standard dose for treating iron deficiency anemia. 1 The British Society of Gastroenterology guidelines explicitly state this is "achieved most simply and cheaply with ferrous sulphate 200 mg three times daily." 1

Add ascorbic acid (vitamin C) 500 mg with each iron dose to enhance absorption, which is particularly critical given the low iron saturation. 1

Important Nuance on Dosing Guidelines

There is a significant divergence in the evidence regarding optimal iron dosing:

• Older guidelines (British Society of Gastroenterology, 2000) recommend ferrous sulfate 200 mg three times daily 1
• Newer evidence (American Gastroenterological Association, recent) suggests once-daily dosing may be equally effective with better tolerability 2

However, for this specific patient with severe anemia (Hb 9.0) and inadequate response to once-daily therapy, the higher three-times-daily dosing is appropriate. 1 Once hemoglobin improves, consider reducing to once-daily for maintenance. 2

Expected Response and Monitoring

• Check hemoglobin at 4 weeks - expect a rise of approximately 2 g/dL (to ~11.0 g/dL) 1, 2
• If hemoglobin fails to rise by 2 g/dL after 3-4 weeks, this indicates poor compliance, continued blood loss, malabsorption, or misdiagnosis 1
• Continue iron therapy for 3 months after hemoglobin normalizes to fully replenish iron stores 1, 2

Investigation of Underlying Cause

In an elderly gentleman, gastrointestinal blood loss is the most likely cause and must be investigated. 1

The British Society of Gastroenterology recommends:

• Upper endoscopy and colonoscopy are indicated in elderly patients with iron deficiency anemia 1
• Do not delay investigation based on age alone, unless severe comorbidity makes investigation inappropriate 1
• Screen for celiac disease with antiendomysial antibody and IgA measurement 2
• Exclude hematuria to rule out urinary tract tumors 1

When to Consider Intravenous Iron

Switch to IV iron if: 2

• Intolerance to at least two different oral iron preparations (try ferrous gluconate or ferrous fumarate if ferrous sulfate causes side effects) 1
• No improvement in ferritin after 4 weeks of compliant oral therapy 2
• Active inflammatory bowel disease is discovered during investigation 2
• Post-bariatric surgery anatomy affecting absorption 2
• Ongoing gastrointestinal bleeding exceeding oral replacement capacity 2

Special Considerations for Elderly Patients

Use caution with high-dose iron in vulnerable elderly patients - the European Society of Cardiology recommends "low-dose oral iron therapy in vulnerable elderly" to minimize gastrointestinal side effects. 1 However, this must be balanced against the need for adequate treatment of significant anemia.

Monitor for iron overload - the elevated ferritin (290 ng/mL) requires monitoring to avoid excessive iron accumulation. 1

Assess comorbidities - the appropriateness of aggressive investigation should be discussed with the patient, considering comorbidities and whether results would influence management. 1

Common Pitfalls to Avoid

• Do not continue inadequate once-daily dosing when the patient has failed to respond - this represents therapeutic inertia 1
• Do not stop iron when hemoglobin normalizes - continue for 3 months to replenish stores 1, 2
• Do not overlook vitamin C supplementation - this significantly enhances absorption in patients with low iron saturation 1, 2
• Do not fail to investigate the underlying cause - treating iron deficiency without identifying the source of blood loss is inadequate management 1, 2
• Do not use faecal occult blood testing - it is insensitive and non-specific 1

Follow-Up Protocol

Once hemoglobin normalizes: 1

• Monitor hemoglobin and red cell indices every 3 months for one year, then again after another year
• Give additional oral iron if hemoglobin or MCV falls below normal
• Check ferritin in doubtful cases
• Further investigation is only necessary if hemoglobin cannot be maintained with iron supplementation