The new BSG guidelines are designed to promote effective management of iron deficiency anaemia according to a simple scheme, explains Dr Brian Scott
- Iron deficiency anaemia is common, affecting 2–5% of adult men and non-menstruating women
- Gastrointestinal pathology is responsible for most cases of iron deficiency anaemia
- Upper gastrointestinal endoscopy with small bowel biopsy and colonoscopy or barium enema should be considered in all patients, and are usually sufficient
- Menstruating women below 45 years of age may not need these investigations in the absence of gastrointestinal symptoms or a strong family history of colorectal cancer – an endomysial antibody test will suffice
- Treatment with oral iron until the full blood count has been normal for 3 months is recommended. Three-monthly checks for a year and then a check after a further year will detect the need for further treatment
- Further investigation is usually indicated only if the full blood count cannot be maintained in this way
Iron deficiency anaemia is a common condition encountered by most clinicians. It is often detected incidentally when patients have 'routine' blood tests – which always include a full blood count. It has been estimated to occur in 2–5% of adult men and postmenopausal women in the developed world.
While menstrual blood loss is the most common cause of iron deficiency anaemia in premenopausal women, blood loss from the gastrointestinal tract is the most common cause in adult men and postmenopausal women.
Asymptomatic colonic and gastric carcinoma may present with iron deficiency anaemia, and exclusion of these conditions is of prime concern.
Malabsorption (most frequently due to coeliac disease), poor dietary intake, previous gastrectomy and non-steroidal anti-inflammatory drug (NSAID) use are not unusual causes of iron deficiency anaemia, but there are many other possible causes (see Table 1, below).
Table 1: Gastrointestinal diseases presenting with iron deficiency*
|Occult gastrointestinal blood loss|
|Water melon stomach|
|Lymphoma, leiomyoma and other small bowel tumours|
|Duodenal polyp (Brunner's gland adenoma)|
|Carcinoma of the ampulla of Vater|
|Gastrectomy (partial and total) and gastric atrophy|
|Gut resection or bypass|
|†Although common causes of acute bleeding, they are uncommon causes of occult bleeding|
|* Reproduced from Goddard AF, McIntyre AS, Scott BB, for the British Society of Gastroenterology. Guidelines for the management of iron deficiency anaemia. Gut 2000; 46 (Suppl IV): iv1-iv5, by kind permission of the BMJ Publishing Group.|
Referral to a gastroenterologist is therefore appropriate, and such referrals account for 4–13% of all referrals to a gastroenterology clinic.
The management of iron deficiency anaemia is often suboptimal, and yet attention to the prevalence of the various causes in patients with iron deficiency anaemia can result in a simple management plan.
It was to promote such a plan that the British Society of Gastroenterology (BSG) commissioned guidelines for the management of iron deficiency anaemia that are applicable not only to gastroenterologists but also to any doctor seeing patients with the condition.
The process of drawing up the guidelines began with a Medline search using the term 'iron deficiency anaemia'.
All the abstracts were reviewed and all papers thought to be relevant were obtained. The reference lists of these papers were reviewed and further papers obtained which had not been found in Medline.
The strength or level of the evidence for all the recommendations was indicated by one of three grades:
- Level*** indicates evidenced based on large randomised trials
- Level** indicates evidence based on good evidence from trials, but less convincing, e.g. because of smaller numbers
- Level* indicates evidence based on specialist opinion.
Three of the recommendations were graded ***; ten were graded **, and four were graded *.
The first draft of the guidelines was written by three practising gastroenterologists.
This was then reviewed by the Clinical Services and Standards Committee of the BSG and comments from more than 20 members were considered before amendment of the guidelines by the authors.
The revised guidelines were reviewed again by the same committee and further comments were taken into account in producing the third draft. This was then reviewed by the Council of the BSG and their comments were incorporated into the final draft which was submitted to Gut for publication.1
The date for review of the guidelines was set for April 2004.
Many patients with iron deficiency anaemia are known to have suboptimal management. It may be that the high prevalence and apparently trivial nature of the condition deters clinicians from subjecting their patients to invasive investigations.
The guidelines remind all doctors of the range of possible pathologies, and stress the importance of looking in particular for colonic carcinoma and coeliac disease, since missing these conditions could have far-reaching implications.
However, investigation is by no means the only issue, and guidance is also given on the treatment of the iron deficiency.
A follow-up study2 had shown that many patients are not taking iron despite still being anaemic, and many who are no longer anaemic are still taking iron.
Clinicians are now faced with a bewildering range of gastrointestinal investigations and it is difficult for the non-gastroenterologist to decide which is the most appropriate and the correct order. It is particularly difficult to know how far to investigate when initial tests are negative.
The guidelines contain a flow chart (see Figure 1, below) which summarises best practice and could easily be copied and kept in the clinic for ready reference as an aide-mémoire.
|Figure 1: Flow chart for the management of iron deficiency anaemia in men and non-menstruating women*|
|* Reproduced from Goddard AF, McIntyre AS, Scott BB, for the British Society of Gastroenterology. Guidelines for the management of iron deficiency anaemia. Gut 2000;46 (Suppl IV): iv1-iv5, by kind permission of the BMJ Publishing Group.|
The only situation not dealt with in the flow chart is iron deficiency anaemia in menstruating women – a particularly common problem occurring in 5–10% of such women. This is covered in a separate section.
There are few data on the yield of investigations in this group. The authors take the view that, because of the increasing incidence of important pathology with age, those aged more than 45 years should be managed according to the flow chart, and those younger should not have endoscopy or barium enema in the absence of suggestive symptoms or a strong family history of colorectal carcinoma.
However, with the advent of the simple and fairly reliable endomysial antibody test for coeliac disease, it is recommended that this test be performed in all those who do not have an upper gastrointestinal endoscopy and small bowel biopsy.
The key points of the guidelines are shown in the box (below).
- The full guidelines (cost £4.00) are available from the British Society of Gastroenterology, 3 St Andrews Place, Regent's Park, London NW1 4LB (tel 020 7935 2815), or can be downloaded from the BSG website at http://www.bsg.org.uk
- Goddard AF, McIntyre AS, Scott BB, for the British Society of Gastroenterology. Guidelines for the management of iron deficiency anaemia. Gut 2000; 46 (Suppl IV): iv1-iv5.
- Sahay R, Scott BB. Iron deficiency anaemia – how far to investigate? Gut 1993; 34: 1427-8.