Real-world management of SeHCAT-confirmed bile acid diarrhoea: response to colestyramine and predictors of treatment success.

BACKGROUND: Bile acid diarrhoea (BAD) is an increasingly recognized cause of chronic diarrhoea. The 75-selenium homocholic acid taurine (SeHCAT) test remains the gold standard for diagnosis. The primary pharmacological treatment involves bile acid-binding agents, most commonly colestyramine. This study aimed to review the management of BAD at our centre and to identify factors associated with response to colestyramine. MATERIALS AND METHODS: This single-centre retrospective study included all patients with an abnormal SeHCAT test (retention <15%) from 1 January 2020 to 31 December 2023 associated with chronic diarrhoea. Patients receiving empiric bile acid chelators without prior SeHCAT testing and those under 18 years of age were excluded. The primary endpoint was treatment success with colestyramine, defined as complete or partial clinical response without treatment discontinuation due to intolerance. Univariable comparisons and multivariable logistic regression were performed to identify factors independently associated with treatment success. RESULTS: Ninety-seven patients were included; 72.2% were women, with a mean age of 54.4 ± 15.1 years. Severe BAD was observed in 60.8% of cases. Overall, 77.3% of patients responded to colestyramine (43.2% complete, 34.0% partial). In multivariable analysis, baseline higher number of bowel movements per day was independently associated with a lower probability of treatment success (odds ratio 0.79, 95% confidence interval 0.68-0.92; P = 0.003). Colestyramine failure was generally due to intolerance-related discontinuation (17.5% of the cohort) followed by lack of efficacy (5.1%). No severe adverse events were documented. CONCLUSION: Colestyramine appears to be an effective first-line therapy for BAD in routine clinical practice. However, treatment success in this study reflects both clinical response and tolerability, as treatment failure was more frequently related to intolerance than lack of efficacy.