Should a kidney patient with low iron saturation replace iron?

Iron Replacement for Kidney Patient with Iron Saturation of 19%

Yes, this kidney patient should receive iron replacement, as an iron saturation of 19% is below the recommended threshold of 20% for CKD patients and indicates iron deficiency that requires treatment. 1

Diagnostic Criteria for Iron Deficiency in CKD

The iron saturation (TSAT) of 19% falls below the established cutoff that defines iron deficiency in chronic kidney disease patients:

• TSAT <20% indicates iron deficiency in CKD patients, regardless of dialysis status 1
• This threshold has been validated by KDOQI guidelines as having sufficient sensitivity and specificity for detecting iron deficiency 1
• The probability of iron deficiency increases as TSAT values decrease below 20% 1

Additional assessment needed: You must also check the serum ferritin level to fully characterize the iron deficiency:

• Absolute iron deficiency: TSAT ≤20% AND ferritin <100 ng/mL (non-dialysis/peritoneal dialysis) or <200 ng/mL (hemodialysis) 2
• Functional iron deficiency: TSAT ≤20% AND ferritin >100-200 ng/mL 2

Treatment Recommendations Based on CKD Stage

For Hemodialysis Patients (CKD Stage 5D)

Intravenous iron is the preferred route for hemodialysis patients 1:

• Initial dosing: 100-125 mg IV iron at every hemodialysis session for 8-10 doses 1
• IV iron is superior to oral iron for treating both true iron deficiency and functional iron deficiency in dialysis patients 1
• IV iron can be administered conveniently during dialysis sessions 1
• Maintenance therapy: 25-125 mg IV weekly once TSAT >20% and ferritin >100 ng/mL is achieved 1

Available IV iron products include iron sucrose, ferric gluconate, low-molecular-weight iron dextran, ferric carboxymaltose, iron isomaltoside 1000, and ferumoxytol 1, 3, 4

For Non-Dialysis CKD Patients (Stages 3-5)

Either oral or intravenous iron is acceptable 2, 5:

• Oral iron trial is reasonable as first-line therapy in non-dialysis patients 5
• However, oral iron is often poorly absorbed and associated with gastrointestinal side effects in CKD patients 1
• Switch to IV iron if: oral iron is ineffective, poorly tolerated, or if rapid correction is needed 1

Safety Monitoring and Upper Limits

Iron therapy should be administered with the following safety parameters 1:

• Do not chronically maintain TSAT >50% or ferritin >800 ng/mL 1
• KDIGO 2012 guidelines set upper ferritin limit at 500 ng/mL for hemodialysis patients 1
• Withhold IV iron temporarily if TSAT >50% or ferritin >800 ng/mL for up to 3 months, then reassess 1
• Monitor TSAT and ferritin at least every 3 months during maintenance therapy 1

Important Safety Considerations

Hypersensitivity precautions for IV iron 1, 4:

• Administer only where resuscitative facilities and trained personnel are immediately available 4, 5
• Monitor patients for at least 30 minutes after infusion 1, 4
• Test doses may be advisable for iron dextran but are no longer mandatory for newer preparations 1
• Anaphylaxis-like reactions occur in <1% of administrations 1

Contraindications and cautions 5:

• Withhold IV iron during acute infections (but not during chronic inflammation) 6, 5
• Do not administer to patients with documented iron overload 4
• Avoid in patients with known hypersensitivity to iron products 4

Clinical Outcomes

Expected benefits of iron replacement 1, 7:

• Increases hemoglobin by approximately 0.9-1.8 g/dL 1, 7
• Reduces or delays need for erythropoiesis-stimulating agents (ESAs) 1
• Achieves cost savings of 20-30% by sparing expensive ESA products 1
• 55% of CKD patients may reach target hemoglobin of 12 g/dL with IV iron alone, without ESA 7

Critical Pitfall to Avoid

Do not rely solely on ferritin levels to exclude iron deficiency in CKD patients 1:

• Ferritin is an acute phase reactant and can be falsely elevated during inflammation 1
• Many patients with TSAT <20% will be functionally iron deficient even with ferritin >100 ng/mL 1
• The goal is to improve erythropoiesis, not simply to achieve specific TSAT or ferritin targets 1