From the Guidelines
Low iron on iron studies indicates iron deficiency, which requires treatment with iron supplements, and I recommend taking oral iron supplements such as ferrous sulfate 100-200 mg/day, in divided doses, as the first line of treatment, as suggested by the most recent evidence 1. When treating iron deficiency, it is essential to consider the underlying cause, which could be blood loss, poor dietary intake, malabsorption disorders, or increased iron requirements during pregnancy.
- Iron supplementation should be taken on an empty stomach with vitamin C (like orange juice) to enhance absorption, but if stomach upset occurs, it can be taken with food.
- Avoid taking iron with calcium, dairy products, coffee, tea, or antacids, as these reduce absorption.
- Treatment typically continues for 3-6 months to replenish iron stores completely, even after symptoms improve.
- For severe deficiency or if oral supplements aren't tolerated, intravenous iron formulations may be necessary, and ferric carboxymaltose is a suitable option, which can be infused over 15 min 1. In patients with heart failure and iron deficiency, intravenous iron replacement might be reasonable to improve functional status and quality of life, as suggested by the 2017 ACC/AHA/HFSA focused update 1. It is crucial to note that iron supplementation in the presence of normal or even high ferritin values is not recommended and is potentially harmful 1.
- The diagnosis of iron deficiency can be complicated by the presence of inflammation, and measurements of inflammatory parameters, such as CRP, should be carried out to aid diagnosis 1.
- Transferrin saturation levels > 80% are considered toxic and should be avoided 1.
From the FDA Drug Label
Inclusion criteria prior to randomization included hemoglobin (Hb) <12 g/dL, ferritin ≤100 ng/mL or ferritin ≤300 ng/mL when transferrin saturation (TSAT) ≤30%. Iron deficiency was defined as serum ferritin <100 ng/mL or 100 to 300 ng/mL with TSAT <20%.
The treatment for low iron on iron studies with ferric carboxymaltose (IV) is indicated for patients with:
- Ferritin ≤100 ng/mL or
- Ferritin ≤300 ng/mL when transferrin saturation (TSAT) ≤30%
- Ferritin <100 ng/mL or 100 to 300 ng/mL with TSAT <20% 2 2
From the Research
Low Iron on Iron Studies
- Low iron levels can lead to iron-deficiency anemia and pre-anemic iron deficiency, which are the most frequent pathologies 3.
- Oral iron supplementation is usually the first line of treatment for iron deficiency, with ferrous sulfate being the simplest and most commonly prescribed drug 3, 4.
- However, oral iron supplementation can cause gastrointestinal side effects, reducing compliance, and intravenous iron therapy can be used as an alternative to rapidly achieve therapeutic targets without gastrointestinal complications 3, 5.
- The optimal formulation and dosing strategy for oral iron supplementation are still unclear, and daily low-dose and every-other-day dosing protocols have been attempted to improve absorption and limit side effects 4.
- Studies have compared the effects of different oral iron supplements, such as ferrous sulfate and iron bis-glycinate chelate, on ferritin concentration in schoolchildren with iron deficiency 6.
- Intravenous iron sucrose has been shown to be effective in treating iron deficiency anemia in patients with inflammatory bowel disease, with better gastrointestinal tolerability compared to oral iron sulfate 5.
- Iron deficiency is a significant global health problem, particularly affecting children, premenopausal women, and people in low-income and middle-income countries, and can have clinical and functional impairments even in the absence of anemia 7.