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Iron Deficiency Anaemia in Acute Care

This is an abbreviated version of the full guideline on 'Treatment of Iron Deficiency Anaemia in Adults' which is available on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer).

The guideline does not cover the diagnosis or treatment in the following clinical situations:

  • pregnancy
  • postpartum anaemia
  • surgery / trauma
  • patients with chronic kidney disease (CKD) stages 4–5.

Introduction

Iron deficiency anaemia (IDA) occurs in more severe stages of iron deficiency, when the body is iron deficient to the degree that red blood cell and haemoglobin (Hb) production is reduced. The cause of IDA is often multifactorial, and can be broadly attributed to:

  • dietary deficiency
  • malabsorption e.g. coeliac disease, gastrectomy, Helicobacter pylori infection
  • increased loss - chronic blood loss, especially from the uterus or gastrointestinal tract
  • increased requirement
  • other causes e.g. blood donation, self-harm, haematuria, medication.

Assessment and monitoring

For diagnosis of IDA, see flowchart.

Serum ferritin (SF):

  • most useful test in confirming the diagnosis of IDA;
  • a low SF (<15micrograms/L) provides absolute evidence of iron deficiency;
  • can be elevated by inflammatory processes and can mask iron deficiency;
  • a SF >100micrograms/L generally rules out IDA even in the presence of inflammatory disease;
  • if the results are equivocal, practitioners should consider monitoring the Hb concentration in response to a trial of oral iron.

For further information on the interpretation of iron studies, please refer to the Medicines Update blog article, Diagnosis of IDA - Iron Studies.

Drug therapy / treatment options

Treatment with iron replacement therapy should be considered for patients with clinically relevant IDA in whom the clinical benefit of treatment outweighs any risk. Investigation and treatment of an underlying cause should prevent further iron loss, but all patients should have iron supplementation both to correct anaemia and replenish body stores.

Oral iron (first-line treatment choice)

Give ferrous fumarate oral 210mg two – three times a day.

Hb levels should rise by at least 20g/L over 4 weeks. Treatment should be continued for 3 months after Hb is optimised and then stopped.

If response is poor, consider:

  • non-compliance*
  • continued blood loss with inadequate replacement of iron
  • malabsorption
  • wrong diagnosis
  • other complicating factors, in which case reassess treatment.

*If oral iron treatment is not tolerated, adverse effects should be addressed by:

  • reducing the dose frequency.
  • taking with or after food (note doing so decreases absorption by 40–66%).
  • trying an alternative salt / formulation with a lower content of elemental iron. See table 1 in the full guideline available on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer). 

Intravenous iron (second-line treatment choice)

This does not produce a faster Hb response than oral iron, provided that the oral iron preparation is taken reliably and is absorbed adequately. It may produce severe adverse effects, and should be reserved for patients who meet the inclusion criteria below.

Inclusion criteria

  • Genuine intolerance to oral iron preparations. Iron preparations with a low content of elemental iron must be tried (with food) before acceptance of genuine intolerance to oral iron.
  • Severe IDA and concern regarding the patient's ability to comply with oral iron treatment.
  • Patients with clinically active inflammatory bowel disease (IBD), with previous intolerance to oral iron, with haemoglobin <100g/L, and in patients who need erythropoiesis-stimulating agents.
  • Patients with heart failure (HF) with reduced ejection fraction, New York Heart Association (NYHA) class III with a left ventricular ejection fraction (LVEF) ≤45%, or NYHA class II, LVEF ≤40%, who have a Hb level of 95 to 135g/L and iron deficiency (defined as ferritin <100micrograms/L or <300micrograms/L if transferrin saturation (TSAT) <20%).

Intravenous iron therapy should be initiated by a consultant, specialist trainee or equivalent. Some services may delegate responsibility to nominated non-medical prescribers.

There can be complications with IV iron. See below for details. Administration should only occur during working hours when adequate supervision is available. 

Choice of IV iron agent

Use the treatment decision tool to guide product selection, then see the individual dosing and administration guides for Ferinject® (ferric carboxymaltose) or Monofer® (iron isomaltoside). 

Note: These should be used in conjunction with the checklist for prescribing and administration. See Appendix 3 in the full guideline on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer).

Intravenous iron- complications

Hypersensitivity reactions

These include serious and potentially fatal anaphylactic / anaphylactoid reactions. Caution is needed with every dose of IV iron that is given, even if previous administrations have been well tolerated. Patients should be closely monitored for signs of hypersensitivity during, and for at least 30 minutes after every administration. If hypersensitivity reactions or signs of intolerance occur, the infusion must be stopped immediately. Further details are available in the full guideline on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer). 

Extravasation

Paravenous leakage at the infusion site may lead to irritation and potentially long lasting or permanent brown discolouration at the site of infusion. The most effective safeguard against extravasation is to visually inspect the infusion site regularly. Patients should be informed about the possibility of discolouration and advised to report any signs of irritation or pain at the infusion site. In case of suspected paravenous leakage the infusion must be stopped immediately. Further details are available in the full guideline on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer). 

Intravenous iron - assessing response

Hb and ferritin levels should be rechecked to assess response to IV iron treatment. These should be assessed no earlier than 4 weeks  following treatment. Hb levels should rise by at least 20g/L over 4 weeks.

 

Guideline reviewed and content updated October 2020