What does KDIGO recommend for evaluating and treating iron deficiency with intravenous iron in adult dialysis patients with anemia?

KDIGO Recommendations for Iron Deficiency Evaluation and Treatment in Adult Dialysis Patients with Anemia

For adult hemodialysis patients with anemia, KDIGO recommends intravenous iron as the preferred route of administration, initiating therapy when TSAT ≤20% and ferritin ≤100 ng/mL, with monitoring every 3 months during maintenance therapy. 1

Iron Status Evaluation Criteria

Absolute iron deficiency in dialysis patients is defined as:

• TSAT ≤20% AND ferritin ≤100 ng/mL 1
• These thresholds apply to all adult dialysis patients regardless of ESA therapy status 2

Functional iron deficiency (iron-restricted erythropoiesis) occurs when:

• TSAT ≤20% with elevated ferritin levels 3
• This reflects inadequate iron availability despite adequate stores, commonly due to elevated hepcidin 3

When to Initiate Iron Therapy

KDIGO recommends initiating iron supplementation when:

• TSAT ≤30% AND ferritin ≤500 ng/mL in patients not on ESA therapy, with the goal of increasing hemoglobin without starting ESAs 1
• TSAT ≤20% AND ferritin ≤100 ng/mL in hemodialysis patients on ESA therapy 1

Balance potential benefits (avoiding transfusions, minimizing ESA therapy, reducing anemia symptoms) against risks (anaphylactoid reactions, unknown long-term risks) in individual patients 1

Route of Administration

For hemodialysis patients, intravenous iron is the recommended route:

• IV iron is preferred over oral iron for all hemodialysis patients 1
• Oral iron fails to maintain adequate iron stores in most hemodialysis patients 4, 2
• There is no rationale for prescribing oral iron when IV iron is required, given oral iron's poor efficacy in this population 4

Dosing Regimens for Hemodialysis Patients

Initial repletion course:

• Administer 100-125 mg IV iron at every hemodialysis session for 8-10 doses 2
• Alternative: 500-1,000 mg iron dextran as single infusion after 25 mg test dose 2

Maintenance therapy:

• Requires 25-125 mg/week IV iron to maintain target hemoglobin and iron parameters 2
• If TSAT remains ≤20% and/or ferritin remains <100 ng/mL after initial course, administer another course of 100-125 mg per week for 8-10 weeks 2

Monitoring Strategy

Iron status monitoring frequency:

• Evaluate TSAT and ferritin at least every 3 months during ESA therapy 1
• Test more frequently when initiating or increasing ESA dose, after blood loss, when monitoring response to IV iron course, or when iron stores may become depleted 1

Hemoglobin monitoring:

• Check at least every 3 months during maintenance therapy 5
• More frequent monitoring during therapy initiation or dose adjustments 5

Upper Safety Limits: When to Stop Iron

Discontinue IV iron when:

• TSAT exceeds 50% AND/OR ferritin exceeds 800 ng/mL 2
• Consider stopping when ferritin exceeds 500 ng/mL, as evidence of benefit beyond this threshold is insufficient and risks may increase 2
• Patients are unlikely to respond with further hemoglobin increases beyond these thresholds 4

Safety Precautions

For iron dextran preparations:

• Monitor patients for 60 minutes after initial infusion 1
• Resuscitative facilities (including medications) and personnel trained to evaluate and treat serious adverse reactions must be available 1

For non-dextran IV iron preparations:

• Monitor for 60 minutes after initial dose, though the recommendation strength is lower than for dextran products 1

Withhold IV iron during:

• Active infection, as iron is essential for microbial growth 2

Critical Pitfalls to Avoid

Ferritin interpretation:

• Ferritin acts as an acute-phase reactant and can be falsely elevated by inflammation 2
• Always check TSAT alongside ferritin to avoid missing functional iron deficiency 2
• Normal or elevated ferritin does not exclude iron deficiency in dialysis patients 2

Oral iron in hemodialysis:

• Do not prescribe oral iron for hemodialysis patients, as it is ineffective and causes unnecessary side effects 4, 2

High-dose concerns:

• High-dose IV iron (>200 mg/month) has been associated with increased risk of acute cardiocerebrovascular disease, infections, and mortality 4

Integration with ESA Therapy

Address iron deficiency before initiating ESAs:

• All correctable causes of anemia, including iron deficiency, should be addressed prior to ESA initiation 1

For patients on ESA therapy:

• Administer oral iron (or IV iron in hemodialysis patients) when TSAT ≤20% and ferritin ≤100 ng/mL 1
• Continue iron supplementation to maintain TSAT >20% and ferritin >100 ng/mL 1