Aliment Pharmacol Ther. 2009 Jun 30. [Epub ahead of print]
Systematic review: the prevalence of idiopathic bile acid malabsorption (I-BAM) as diagnosed by SeHCAT scanning in patients with diarrhoea-predominant irritable bowel syndrome (IBS).
Wedlake L, A'hern R, Russell D, Thomas K, Walters J, Andreyev H. Dept of Nutrition & Dietetics, The Royal Marsden Hospital, London and Sutton, UK.
Background: Chronic or recurrent, watery diarrhoea affects one third of patients diagnosed as having irritable bowel syndrome. In the last thirty years, repeated suggestions have been made that idiopathic bile acid malabsorption ('I-BAM') may be the cause of this diarrhoea in patients whose clinicians have failed to consider this as a possibility, or have lacked access to appropriate diagnostic tools. Aim: To determine the prevalence of idiopathic bile acid malabsorption as a cause for unexplained chronic diarrhoea in patients suffering from diarrhoea-predominant irritable bowel syndrome ('IBS-D').
Methods: A systematic search was performed of all publications reporting the proportion of patients presenting with diarrhoea-predominant irritable bowel type symptoms, who were subsequently confirmed as having I-BAM on the basis of a (SeHCAT) test. Data were combined to produce summary estimates of the prevalence of I-BAM amongst this patient group.
Results: 18 (English-language) studies, 15 prospective, published between 1985 and 2007 comprising 1223 patients were identified in which patients diagnosed with IBS-D type were investigated for bile acid malabsorption. Five studies (total: 429 patients) indicated that 10% (CI: 7-13) of patients had severe bile acid malabsorption (SeHCAT 7 day retention <5% of baseline value). 17 studies (total: 1073 patients) indicated 32% (CI: 29 - 35) of patients had moderate bile acid malabsorption (SeHCAT <10%). 7 studies (total: 618 patients) indicated that 26% (CI: 23 - 30) of patients had mild (SeHCAT <15%) bile acid malabsorption. Further, data extracted from 15 of these studies showed that a dose-response relationship existed with respect to the severity of bile acid malabsorption and effectiveness of treatment with bile acid binder, colestyramine. Therapeutic response to treatment was 96% in patients with <5% retention, 80% in patients with <10% retention and 70% in patients with <15% retention.
Conclusions: Idiopathic adult-onset bile acid malabsorption is not rare. International guidelines for the management of irritable bowel syndrome need to be revised so that clinicians become more aware of this possibility.
PMID: 19570102 [PubMed - as supplied by publisher]