Prevalence and clinical features of bile acid diarrhea in patients with chronic diarrhea.

Objective: Bile acid diarrhea is a form of chronic diarrhea caused by excessive bile reaching the colon. Conditions involving the terminal ileum and cholecystectomy are predisposing factors but an idiopathic form of bile acid diarrhea has also been described. In this study we aimed to evaluate the prevalence of bile acid diarrhea in patients consecutively evaluated for chronic diarrhea in an Outpatient Gastroenterology Clinic.

Methods: Medical records of all patients admitted for chronic diarrhea (>4 weeks) between June 2018 and April 2019 were retrospectively reviewed. Bile acid diarrhea was suspected in patients with ileal disease, cholecystectomy or post-prandial diarrhea. Patients' age at diagnosis, sex, presenting symptoms, results of main test and examinations, final diagnoses and date of last follow-up visit were also collected. Exclusion of chronic diarrhea of other causes and a 6-month clinical improvement with cholestyramine treatment confirmed the diagnosis of bile acid diarrhea.

Results: In total, 139 patients aged 46 ± 20 years (76 women and 63 men) were included. Diarrhea due to an organic cause was diagnosed in 16 patients. A clinical response to cholestyramine persisting for more than 6 months led to a diagnosis of bile acid diarrhea in 39 (aged 52 ± 19 years) out of the remaining 123 patients with functional forms of diarrhea. Therefore, the prevalence of bile acid diarrhea was 28.1% (95% confidence interval 19.9%-38.4%) in patients with chronic diarrhea.

Conclusions: Bile acid diarrhea is a very common, yet under-recognized cause of chronic functional diarrhea. A therapeutic trial of cholestyramine is a valid diagnostic strategy.