SeHCAT (tauroselcholic [75selenium] acid) for the investigation of bile acid diarrhoea in adults: a systematic review and cost-effectiveness analysis

Abstract

Background: Tauroselcholic [75selenium] acid (SeHCAT™) (GE Healthcare, Chicago, IL, USA) is a radiopharmaceutical that may be useful in diagnosing bile acid diarrhoea. Objectives: To assess the clinical effectiveness and cost-effectiveness of SeHCAT for the investigation of adults with chronic unexplained diarrhoea, diarrhoea-predominant irritable bowel syndrome or functional diarrhoea (suspected primary bile acid diarrhoea), and adults with chronic diarrhoea and Crohn’s disease who have not undergone ileal resection (suspected secondary bile acid diarrhoea). Methods: Sixteen databases were searched to November 2020. The review process included measures to minimise error and bias. Results were summarised by primary or secondary bile acid diarrhoea and study quality was considered. The cost-effectiveness analysis combined a short-term (6-month) decision-analytic model (diagnosis and initial treatment response) and a lifetime Markov model comprising three health states (diarrhoea, no diarrhoea and death), with transitions determined by probabilities of response to treatment. Analyses were conducted from an NHS and Personal Social Services perspective. Results: Twenty-four studies were included in this review. Of these, 21 were observational studies, reporting some outcome data for patients treated with bile acid sequestrants, and in which only patients with a positive SeHCAT test were offered bile acid sequestrants. The median rate of response to bile acid sequestrants, among patients with a 7-day SeHCAT retention value of ≤ 15%, was 68% (range 38–86%) (eight studies). The estimated sensitivity of SeHCAT (≤ 15% threshold) to predict positive response to colestyramine was 100% (95% confidence interval 54.1% to 100%) and the specificity estimate was 91.2% (95% confidence interval 76.3% to 98.1%) (one study). The median proportion of treated patients who were intolerant/discontinued bile acid sequestrants was 15% (range 4–27%) (eight studies). There was insufficient information to determine whether or not intolerance varied between colestyramine, colestipol and colesevelam. For both populations, the SeHCAT 15% (i.e. a SeHCAT retention value of ≤ 15%) strategy dominated other strategies or resulted in incremental cost-effectiveness ratios of 15% could benefit from treatment with bile acid sequestrants. Although the results of the economic evaluation conducted for both populations indicated that the SeHCAT 15% strategy dominated the other two strategies or resulted in incremental cost-effectiveness ratios that were lower than the common thresholds of £20,000 or £30,000 per quality-adjusted life-year gained, the paucity and poor quality of evidence mean that uncertainty is high. Future work: The optimum study design would be a multiarm randomised controlled trial, in which participants meeting the inclusion criteria are randomised to receive colestyramine, colestipol, colesevelam or placebo, and all participants receive SeHCAT testing. Study registration: This study is registered as PROSPERO CRD42020223877. Funding: This project was funded by the National Institute for Health and Care Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 26, No. 45. See the NIHR Journals Library website for further project information.

Keywords

• bile acids
• diarrhoea
• malabsorption
• chronic disease
• diagnosis
• irritable bowel syndrome
• crohn’s disease