Treatment of iron deficiency anaemia in primary care – a review
Where possible treat the underlying cause Ensure that a referral is made for further investigations where a referral criteria is met to r/o a serious underlying cause as gastric erosion or cancer All patients need iron replacement Treatment improves QoL and physical condition as well as alleviates fatigue and cognitive deficits Aim of treatment is to ◘ restore hemoglobin level ◘ replenish iron stores
Oral iron therapy is inexpensive and effective but the bioavailability of iron is relatively low Efficiency of iron absorption increases as IDA become more severe Ferrous salts have minimal difference between them in efficiency of absorption of iron CDC recommends 50-60 mg of oral elemental iron BD for 3 months for the therapeutic Rx of IDA Adding ascorbic acid ( 250-500 mg bd ) with iron may enhance iron absorption Take on an empty stomach and avoid other medications at the same time as antacids If SEs prominent consider using BD or preparations with lower iron content or even alternate days to improve tolerance ( alternate day administration has been supported from data of an observational trial ) BNF advice against the use of modified release preparations as they do not offer any therapeutic advantage ( they may not be absorbed in stomach ) Most common iron preparations are ferrous sulfate , gluconate and fumarate Ferric containing preparation have poor solubility.
Nausea Vomiting Constipation Abdominal pain Metallic taste Dark stools ( it does not produce false + ve results for occult blood ) GI side effects are dose dependent and result in poor adherence in 10% to 50 % of patients In malaria endemic area this may reverse the potentially protective effects of iron deficiency
Ideally taken on an empty stomach ( food can reduce iron absorption ) Advice that side effects usually settle down with time If SEs troublesome advise to take before or after food Reduce the dose Consider an alternative preparation for e.g with lower iron content.
Commence oral iron replacement- FBC could be repeated in 2-4 weeks time after start of iron replacement- Test at 2-4 months again- Once Hb is in range / other indices are normal continue for another 3 months and then stop.
Reticulocyte count – early indicator of response to iron therapy increases within a few days and can be appreciated as early as 1 week.
Haemoglobin- usually increases within 2-3 wks a rise of 2.0 g / dL over 3 weeks can be predicted.
Ferritin- valuable as it is not influenced by daily variations in iron intake only starts to normalise once anaemia starts to resolve progressive rise indicates compliance and that body’s iron stores are being replenished
Serum transferrrin receptor
MCV will rise with Hb
Check FBC every 3 months for 1 year. Recheck after 1 year and if symptoms of anaemia develop , if indicated re-prescribe iron.
Refer for further investigations if Hb/ red cell indices cannot be maintained at normal levels Prophylactic iron therapy can be considered for those who are at particular risk of developing iron deficiency anaemia , these groups include ○ recurring anaemia in elderly in whom further investigation may not be appropriate / desired/ indicated ○ vegans ○ known coeliac disease ○ heavy menstrual bleed ○ h/o operations as gastrectomy ○ pregnant women ○ seek advise from renal team if on dialysis as prophylactic iron may also be beneficial in this group.
Poor response- Hb does not increase satisfactorily ie ◘ < 2g / 100 ml Non-compliance for e.g due to GI SEs Insufficient length of treatment Ongoing blood loss – inadequate replacement ie the concomitant / causal condition remains unresolved Duodenum- poor absorption ♦ GI pathology for e.g inflammatory bowel disease or any other cause of chronic inflammation ♦ malignancy ♦ insufficient gastric acidity – for e.g due to pharmacological blockade of gastric secretion Incorrect diagnosis for e.g anaemia of chronic disease ( AOCD ) Other deficiencies ? B 12 / folate Iron-refractory iron deficiency anaemia ( IR-IRDA ) Rare genetic anaemias.
Refer for further investigations / specialist assessment.
Intravenous iron therapy- IV iron circumvents the problem of iron absorption More effective Increases Hb level more rapidly than oral iron Large doses can be provided with a single infusion Previous products for IV replacement ( Dextran ) were associated with an increased risk of anaphylactic reactions but newer products are deemed safer ( e.g Venofer ) IV iron replacement is expensive.
Consider IV iron if – Rapid correction of severe symptomatic anaemia Degree of anaemia is likely to cause cardiovascular instability Patients on hemodialysis Functional iron deficiency when ESA is being used for e.g ○ anaemia of chronic disease ○ inflammatory diseases ○ anaemia of cancer ( CRA ) Acquired or hereditary decreased intestinal absorption and / or liberation of iron from macrophages Unable to absorb due to h/o surgery for e.g gastrectomy Intolerance or non compliance with iron treatment Chronic GI bleeding with poor response to oral iron therapy and GI interventions e.g ○ angiodysplasia ○ hereditary haemorrhagic telangiectasia During chemotherapy or radiation therapy for cancer Pre-operative IDA before elective surgery which may incur high blood loss Post partum anaemia Anaemia in ICU patients.
IM iron injections ( painful and require several injections ) can cause long term skin complications and are not preferred in clinical practice.
- Ipswich and East Suffolk Guidance on prescribing iron supplements in primary care https://ipswichandeastsuffolkccg.nhs.uk/Portals/1/Content/Members%20Area/Clinical%20Area/Medicine%20managment/Medical%20conditions/Bone%20Health/Iron%20Prescribing%20Guidance%20.pdf
- Goddard, A.F., James, M.W., McIntyre, A.S. and Scott, B.B. (2011) Guidelines for the management of iron deficiency anaemia. Gut 60(10), 1309-1316.
- CKS – IDA management https://cks.nice.org.uk/topics/anaemia-iron-deficiency/management/
- Jimenez, Kristine et al. “Management of Iron Deficiency Anemia.” Gastroenterology & hepatology vol. 11,4 (2015): 241-50.
- Buckinghamshire NHS Trust- Iron deficiency anaemia http://www.bucksformulary.nhs.uk/docs/Guideline_802FM.pdf
- Iron therapy Carlo Brugnara , Photis Beris ESH Org via *IRON2009 (esh.org)
- A physicians guide to oral iron supplements Provided by the Society for the Advancement of Blood Management, iron.sabm.org *Microsoft Word – 2A2 PhysiciansGuideOralIronWEBFINAL Final Review 1.19.doc (sabm.org)
- BNF Anaemia , iron deficiency Anaemia, iron deficiency | Treatment summary | BNF content published by NICE