Effectiveness of diet, psychological, and exercise therapies for the management of bile acid diarrhoea in adults: A systematic review

BACKGROUND: Bile acid diarrhoea (BAD) causes chronic diarrhoea and is primarily treated pharmacologically. This systematic review aimed to evaluate the effectiveness of non‐pharmacological therapies for evidence‐based management of BAD in adults. METHODS: A systematic review of the medical literature was performed from 1975 to 13 July 2021 to identify studies on diet, psychological, and exercise therapies that met diagnostic criteria for BAD in adults with diarrhoea. Effectiveness was judged by responder or improvement in diarrhoea at study endpoint according to each study's definition of diarrhoea. Therapeutic effect on abdominal pain and flatulence was also measured. Risk of bias was assessed using the Risk Of Bias In Non‐Randomised Studies of Interventions tool. A narrative review was conducted using ‘Synthesis Without Meta‐analysis’ guidance. Certainty of the evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation. RESULTS: Eight prospective cohort studies were identified on diet therapies from 2 weeks to over 2 years involving 192 patients. No psychological or exercise therapies were found. Carbohydrate modification (one study, n = 2) in primary BAD, and dietary fat intake reductions (five studies, n = 181) and an exclusive elemental diet therapy (two studies, n = 9) in secondary BAD, showed beneficial directions of effect on diarrhoea, abdominal pain, and flatulence. Risks of bias for each study and across studies for each therapy type were serious. Certainty of the evidence was very low for all outcomes. CONCLUSIONS: No conclusions could be drawn on the effectiveness of diet, psychological, or exercise therapies on diarrhoea, abdominal pain, and flatulence for the management of BAD in adults. High‐quality randomised controlled trials are needed.