Iron Deficiency Anaemia (IDA) occurs in 2-5% of adult men and postmenopausal women in the developed world and is a common cause of referral to gastroenterologists (4-13% of referrals). While menstrual blood loss is the most common cause of IDA in premenopausal women, blood loss from the GI tract is the most common cause in adult men and postmenopausal women. Asymptomatic colonic and gastric carcinoma may present with IDA, and seeking these conditions is a priority in patients with IDA. Malabsorption (most commonly from coeliac disease in the UK), poor dietary intake, blood donation, gastrectomy and use of non-steroidal anti-inflammatory drugs (NSAIDs) are common causes of IDA, and there are many other possible causes . IDA is often multifactorial. Its management is often suboptimal, with most patients being incompletely investigated or not investigated at all. Dual pathology - that is, the presence of a significant cause of bleeding in both upper and lower GI tracts - may occur in 1-10% of patients or more and should be increasingly considered the older the patient.
These guidelines are primarily intended for Western gastroenterologists and gastrointestinal (GI) surgeons, but are applicable for other doctors seeing patients with iron deficiency anaemia (IDA). They are not designed to cover patients with overt blood loss or those who present with GI symptoms. GI symptoms or patients at particular risk of GI disease should be investigated on their own merits.