What are the implications of low iron and severely low ferritin levels?

From the Guidelines

Iron deficiency with severely low ferritin levels should be treated with iron supplementation to prevent or treat anemia, and the most effective approach is to take an oral iron supplement, such as ferrous sulfate 100-200 mg/day, in divided doses, as recommended by the espen micronutrient guideline 1.

Recommendation

• Take an oral iron supplement, such as ferrous sulfate 100-200 mg/day, in divided doses, to replenish iron stores and prevent or treat anemia.
• Consider alternate day dosing to improve iron resorption and minimize gastrointestinal side effects, as suggested by recent data 1.
• If oral supplementation is not effective or feasible, IV iron administration may be necessary, with ferric carboxymaltose being a suitable option, as it can be infused over 15 minutes and has been shown to reduce length of hospital stay and 90-day mortality in inflammatory anemic critically ill patients 1.

Additional Information

• Take iron supplements with vitamin C (like orange juice) to enhance absorption.
• Avoid taking iron with calcium, coffee, or tea, as these can reduce absorption.
• Monitor for gastrointestinal side effects, such as constipation, diarrhea, and nausea, which are common with iron therapy.
• Recheck iron and ferritin levels after at least 3 months of supplementation to assess the effectiveness of treatment.

Reasoning

Severely low ferritin levels indicate depleted iron stores, and iron supplementation is necessary to replenish these stores and prevent or treat anemia. The espen micronutrient guideline 1 recommends treating iron deficiency with oral or parenteral iron supplementation, and the choice of treatment depends on the individual patient's needs and medical history. By prioritizing the most recent and highest quality study, we can provide an evidence-based recommendation for the treatment of iron deficiency with severely low ferritin levels.

From the Research

Implications of Low Iron and Severely Low Ferritin Levels

• Low iron and severely low ferritin levels can have significant implications for patients, particularly those with chronic heart failure or peritoneal dialysis patients 2, 3.
• Iron deficiency can occur in half or more of heart failure sufferers, depending on age and the phase of the disease, and can be a cause of anaemia, but it is also common even without anaemia 4.
• A serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 μg/L are commonly used criteria to define iron deficiency, but these criteria may not accurately identify an absolute or functional iron deficiency state 2.
• A low baseline TSAT, but not serum ferritin level, appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events 2.
• Patients with a TSAT <20% may benefit from intravenous iron therapy, regardless of their serum ferritin level, while those with a TSAT ≥20% may not benefit from such therapy 2.

Diagnostic Criteria for Iron Deficiency

• The use of a serum ferritin level <100 μg/L alone as a diagnostic criterion for iron deficiency may not be reliable, as patients with a serum ferritin level >100 μg/L may still be iron deficient 5.
• A combination of serum ferritin, transferrin saturation, and/or the percentage of hypochromic red cells should be used to assess iron status in peritoneal dialysis patients 3.
• The soluble transferrin receptor/Log(10)ferritin ratio (sTfR-F Index) may be a useful determinant of body iron stores and can help identify patients with iron deficiency 5.

Treatment of Iron Deficiency

• Intravenous iron therapy may be effective in reducing the risk of cardiovascular death or total heart failure hospitalization in patients with iron deficiency and a TSAT <20% 2.
• Oral iron supplementation may be preferred in some cases, but parenteral iron supplementation may be required in patients who do not respond to oral therapy or who have a severe iron deficiency 3.
• The optimal form and dosage of intravenous iron supplementation are still unclear and may depend on individual patient factors 3.