What is the recommended management for a 78‑year‑old man with chronic kidney disease and a hemoglobin of 8.4 g/dL who is taking oral ferrous sulfate 325 mg daily?

Management of Anemia in a 78-Year-Old Male with CKD on Oral Iron

This patient requires a switch from oral ferrous sulfate to intravenous iron therapy, as oral iron is inadequate for managing anemia in advanced CKD and most non-dialysis CKD patients cannot maintain adequate iron stores with oral supplementation alone. 1

Why Oral Iron is Insufficient in This Patient

• Oral iron fails to maintain adequate iron status in most CKD patients, particularly those with advanced disease, due to reduced absorption, ongoing blood losses, and increased hepcidin levels that block intestinal iron uptake 1
• The patient's hemoglobin of 8.4 g/dL is well below the target range of 11-12 g/dL for CKD patients, indicating that the current oral ferrous sulfate 325 mg daily regimen is ineffective 1
• There is no rationale for continuing oral iron when it has clearly failed, given its poor efficacy, inconvenience, cost, and gastrointestinal side effects in the CKD population 2

Essential First Step: Check Iron Parameters

Before initiating IV iron, you must measure transferrin saturation (TSAT) and serum ferritin to confirm iron deficiency and guide treatment 1:

• Absolute iron deficiency in CKD is defined as TSAT ≤20% and ferritin ≤100 ng/mL (for non-dialysis patients) 1, 3
• Functional iron deficiency occurs when TSAT <20% despite ferritin 100-500 ng/mL, especially common in patients who may later require erythropoiesis-stimulating agents (ESAs) 3
• Iron supplementation should be initiated when TSAT ≤30% and ferritin ≤500 ng/mL to increase hemoglobin without starting ESA therapy 1, 4

Recommended IV Iron Regimen for Non-Dialysis CKD

Initial repletion phase 4, 5:

• Administer 500 mg IV iron sucrose initially, followed by 500 mg IV 4 weeks later (total 1000 mg over 4 weeks) 4
• Alternative dosing: 200 mg IV every 2 weeks for 5 doses (total 1000 mg over 8 weeks) 5, 6
• A test dose of 25 mg is required before initiating therapy to monitor for allergic reactions 3

Target iron parameters during treatment 4, 3:

• Maintain TSAT ≥20% and ferritin ≥100 ng/mL as minimum thresholds 1, 3
• Optimal targets are TSAT ≥30% and ferritin 400-600 ng/mL for best hemoglobin response 4
• Stop iron supplementation when ferritin exceeds 500-800 ng/mL or TSAT exceeds 50%, as further increases are unlikely and may pose safety risks 1, 4

Monitoring Schedule

• Check hemoglobin 2-4 weeks after completing the iron course to assess response 4
• Wait at least 4 weeks before rechecking ferritin and TSAT after IV iron, as both become falsely elevated immediately post-infusion 4
• Once treatment is established, check TSAT and ferritin every 3 months 1, 4
• Monitor hemoglobin every 3 months for CKD stage 4-5 patients 4

Critical Safety Considerations

Cardiovascular and infection risks with IV iron 6:

• A 2015 randomized trial in non-dialysis CKD patients found that IV iron was associated with increased serious cardiovascular events (adjusted incidence rate ratio 2.51) and infections requiring hospitalization (adjusted incidence rate ratio 2.12) compared to oral iron 6
• Despite this, IV iron remains the preferred treatment because oral iron is ineffective in most CKD patients, and the benefits of correcting anemia outweigh risks when used appropriately 1, 4
• Monitor patients for at least 30 minutes after infusion and have personnel and therapies immediately available to treat anaphylaxis 3

When to Consider ESA Therapy

• Always optimize iron status first before initiating ESA therapy, as approximately 59% of non-dialysis CKD patients respond to IV iron alone without requiring ESAs 4
• Consider ESA therapy only if hemoglobin remains <10 g/dL despite achieving target iron parameters (TSAT ≥20%, ferritin ≥100 ng/mL) 1
• ESA therapy should be used with great caution in elderly patients, particularly those with history of stroke or malignancy 1

Common Pitfalls to Avoid

• Do not assume normal ferritin means adequate iron, as ferritin is an acute-phase reactant and can be falsely elevated by inflammation; always interpret ferritin together with TSAT 1, 4, 3
• Do not continue oral iron indefinitely when it has failed—most CKD patients require IV iron to achieve and maintain adequate iron stores 1, 2
• Evaluate for occult GI bleeding in non-dialysis CKD patients with confirmed iron deficiency, especially in elderly patients, as GI pathology may be contributing 1, 4
• Do not withhold iron solely because ferritin is elevated when TSAT is low—this combination indicates functional iron deficiency requiring treatment 3