Should patients with anemia of chronic kidney disease (CKD) be prescribed supplemental iron?

Iron Supplementation for Anemia in Chronic Kidney Disease

Patients with anemia of chronic kidney disease should receive intravenous iron supplementation rather than oral iron, as IV iron more effectively improves hemoglobin levels, reduces mortality, and enhances quality of life by addressing both absolute and functional iron deficiency common in CKD. 1, 2

Diagnostic Criteria for Iron Deficiency in CKD

Iron status should be evaluated in all CKD patients before and during treatment using:

• Transferrin saturation (TSAT): Target >20%
• Serum ferritin: Target >100 ng/mL for non-dialysis CKD and >200 ng/mL for hemodialysis patients

Iron deficiency is defined as:

• TSAT ≤20% and ferritin ≤100 ng/mL in non-dialysis and peritoneal dialysis patients
• TSAT ≤20% and ferritin ≤200 ng/mL in hemodialysis patients 1, 3

Administration Protocol

For Hemodialysis Patients:

• Initial dosing: 100-125 mg IV iron at each hemodialysis session for 8-10 doses
• Maintenance dosing: 25-125 mg IV weekly once target levels are achieved
• Frequency options: Can be given thrice weekly, twice weekly, weekly, or every other week, providing 250-1,000 mg within 12 weeks 1, 2

For Non-Dialysis and Peritoneal Dialysis Patients:

• Preferred approach: IV iron administration of 500-1,000 mg as a single infusion, repeated as needed 1
• A 1-3 month trial of oral iron may be attempted first, but is often ineffective due to poor absorption 1, 4
• For those requiring larger doses, administer 500-1,000 mg IV iron diluted in 250 mL normal saline over 1 hour 1

Monitoring Protocol

• Check TSAT and ferritin every 3 months during maintenance therapy
• Monitor hemoglobin at least monthly until stable
• For patients receiving ESA therapy, check iron status every 3 months
• Wait at least 7 days after IV iron administration before measuring iron parameters if doses of 100-125 mg are given
• Wait at least 14 days after administration of doses ≥1,000 mg 1, 2

Precautions and Contraindications

• Withhold IV iron during active infections
• Use caution with iron dextran due to potential for anaphylactic reactions; consider test dose of 25 mg
• Avoid excessive iron administration to prevent iron overload (maintain ferritin <500 ng/mL) 1, 2, 5
• Be aware that IV iron dextran may cause dose-related arthralgias and myalgias, especially with doses >100 mg 1

Pediatric Considerations

For pediatric patients, adjust dosing by weight:

• Weight <10 kg: 25 mg per dose (10-dose course) or 125 mg total dose
• Weight 10-20 kg: 50 mg per dose (10-dose course) or 250 mg total dose
• Weight >20 kg: 100 mg per dose (10-dose course) or 500 mg total dose 1

Rationale for IV Iron Preference

1. Oral iron fails to maintain adequate iron stores in most hemodialysis patients due to poor absorption and gastrointestinal side effects
2. IV iron increases hemoglobin/hematocrit levels more effectively, improving morbidity and survival
3. IV iron reduces the need for higher doses of erythropoiesis-stimulating agents (ESAs), which carry cardiovascular risks
4. Health benefits of IV iron exceed its adverse effects, resulting in net health benefit 1, 2, 4

Available IV Iron Formulations

Several IV iron preparations are available with varying efficacy:

• Iron dextran (INFeD, Dexferrum)
• Ferric sodium gluconate (Ferrlecit)
• Iron sucrose
• Ferumoxytol and ferric carboxymaltose (may be more potent based on network meta-analysis) 1, 6

By following these guidelines for iron supplementation in CKD patients, clinicians can effectively manage anemia, reduce the need for blood transfusions, and improve patient outcomes.