Systematic review: the prevalence of idiopathic bile acid malabsorption as diagnosed by SeHCAT scanning in patients with diarrhoea-predominant irritable bowel syndrome.
BACKGROUND
Recurrent, watery diarrhoea affects one-third of patients diagnosed with irritable bowel syndrome ('IBS-D'). Idiopathic bile acid malabsorption ('I-BAM') may be the cause.


OBJECTIVE
To determine the prevalence of I-BAM in patients suffering from IBS-D.


METHODS
A systematic search was performed of publications reporting patients presenting with IBS-D type symptoms, who were subsequently confirmed as having I-BAM by SeHCAT scanning.


RESULTS
Eighteen relevant studies, 15 prospective, comprising 1223 patients were identified. Five studies (429 patients) indicated that 10% (CI: 7-13) patients had severe bile acid malabsorption (SeHCAT 7 day retention <5% of baseline value). 17 studies (1073 patients) indicated that 32% (CI: 29-35) patients had moderate bile acid malabsorption (SeHCAT <10%). 7 studies (618 patients) indicated that 26% (CI: 23-30) patients had mild (SeHCAT <15%) bile acid malabsorption. Pooled data from 15 studies showed a dose-response relationship according to severity of malabsorption to treatment with a bile acid binder: response to colestyramine occurred in 96% of patients with <5% retention, 80% at <10% retention and 70% at <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.
Wedlake
L
L
Department of Nutrition & Dietetics, The Royal Marsden Hospital, London and Sutton, UK.
A'Hern
R
R
Russell
D
D
Thomas
K
K
Walters
J R F
JR
Andreyev
H J N
HJ
D000328:Adult; D000837:Anion Exchange Resins / Q000627:therapeutic use*; D001647:Bile Acids and Salts / Q000378:metabolism*; D002792:Cholestyramine Resin / Q000627:therapeutic use*; D003967:Diarrhea / Q000453:epidemiology / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D008286:Malabsorption Syndromes / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D015995:Prevalence; D011446:Prospective Studies; D012189:Retrospective Studies; D012720:Severity of Illness Index
D000837:Anion Exchange Resins; D001647:Bile Acids and Salts; D002792:Cholestyramine Resin