Mon 17 October 16

Bile Acid Diarrhoea: evidence for lower SeHCAT retention in type 3 patients following cholecystectomy

John McLaughlin, Robert Logan, Fiona Dorothy Alexandra Reid, Jennifer Summers

Introduction: Bile Acid Diarrhoea (BAD) is an under-recognised cause of chronic diarrhoea and can be assessed by measuring SeHCAT retention. BAD can relate to terminal ileal disease or resection (designated as Type 1), be considered as idiopathic (type 2), or be linked to other underlying conditions (Type 3). Its prevalence is increased following cholecystectomy, but the clinical profile and severity of bile acid malabsorption are poorly characterised. Aims & Methods: A prospective study evaluated SeHCAT usage across the United Kingdom was undertaken, capturing data from 38 centres and 1,036 patients. Aims were to investigate SeHCAT retention rates according to the type of BAD suspected, and to evaluate centre-defined abnormal results. Result: Of the 1,036 patients, 752 had information on suspected BAD type, of whom 310 had suspected Type 3 BAD (71% female, mean age 49 years). A large subset were identified as post-cholecystectomy (n = 98, 82% female, mean age 52 years) and non post-cholecystectomy (n = 212, 67% female, mean age 48 years). Suspected Type 3 are hereon referred to as BAD Types 3a (all except post-cholecystectomy) and 3b (post-cholecystectomy only). Patients with suspected BAM Type 3a had the largest mean retention of 25% (95% CI: 22.3–28.0%, median = 20, while post-cholecystectomy patients (BAD Type 3b) had a mean retention of 15% (95% CI: 11.7–18.3%, median = 9). These compare to mean retentions of 9% in suspected Type 1 and 21% in Type 2 (1). Centre-defined abnormal results were higher amongst suspected Type 3b patients (56%) than Type 3a (30%), with correspondingly higher bile acid sequestrant prescriptions for Type 3b patients (49%) than Type 3a (25%) at the time of the survey. Conclusion: Subdivision of BAD Type 3 patients suggest (although not conclusively given the limitations of this survey) that post-cholecystectomy patients have a physiologically different profile compared to non post-cholecystectomy Type 3a patients, with more severe bile acid malabsorption. This warrants separate analysis in future research.