Patients with gastrointestinal disorders frequently present with iron deficiency1. In patients with inflammatory bowel disease, the prevalence of iron deficiency has been reported to range from 36 to 90%2.
The duodenum and upper jejunum are the primary routes of dietary iron absorption and dysfunction of these structures can result in malabsorption of iron and iron deficiency. The gastrointestinal tract is also a common site of chronic blood loss, which can deplete the body’s iron stores.
Digestive aetiologies of iron deficiency
Gastrointestinal aetiologies of iron deficiency include malignant and non-malignant lesions as well as inflammatory conditions (see table below). Iron deficiency without anaemia can act as a potential indicator for gastrointestinal malignancy, which has an incidence five times higher in iron-deficient versus iron-replete men and postmenopausal women3.
Table 1. Common gastrointestinal aetiologies of iron deficiency4
Consequences of iron deficiency in gastrointestinal disorders
Iron deficiency is associated with serious health disorders including fatigue, cognitive impairment and tachycardia, and iron supplementation has been shown to provide significant benefits in iron-deficient patients with these conditions5.
Iron deficiency may also feature in the pathogenesis of gastrointestinal disorders and has been shown to accelerate the development of H. pylori-induced gastric lesions (see ‘What are the clinical implications of iron deficiency in patients with gastrointestinal disorders?’).
Iron deficiency anaemia in gastrointestinal disorders
Iron deficiency is also the major cause of anaemia6, and iron deficiency anaemia represents 4–13% of all referrals to gastroenterologists7. In colorectal cancer, iron deficiency anaemia is an independent predictor of reduced disease-free survival8.