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, 9 (7), e029573

Multicentre Endoscopist-Blinded Randomised Clinical Trial to Compare Two Bowel Preparations After a Colonoscopy With Inadequate Cleansing: A Study Protocol


Multicentre Endoscopist-Blinded Randomised Clinical Trial to Compare Two Bowel Preparations After a Colonoscopy With Inadequate Cleansing: A Study Protocol

Michael Sai Lai Sey et al. BMJ Open.


Introduction: Inadequate bowel preparation is common and negatively impacts colonoscopy quality. The objective of this study is to compare two bowel preparation regimens in cleansing the colon after an index colonoscopy with failed bowel preparation.

Methods and analysis: This is a phase III, multicentre, randomised clinical trial comparing two bowel preparation regimens after failure to adequately cleanse at the index colonoscopy. Regimen A consists of 4 L split-dose polyethylene glycol electrolyte solution (PEG-ELS) and Regimen B consists of 6 L split-dose PEG-ELS, both preceded by 15 mg of bisacodyl the day before the procedure along with a low-fibre diet 3 and 2 days before the procedure followed by a clear fluid diet starting the day before the procedure. The primary outcome is adequate bowel preparation, defined as a Boston Bowel Preparation Scale (BBPS) score of ≥6 with each segment score ≥2. Secondary outcomes include mean BBPS score, bowel preparation adequacy using the US Multi-Society Task Force on Colorectal Cancer definition, detection rate by polyp subtype, caecal intubation rate, mean Validated Patient Tolerability Questionnaire for Bowel Preparation score, subject willingness to repeat the preparation and faecal incontinence rate.

Ethics and dissemination: The study will be conducted in accordance with Good Clinical Practice guidelines and local institutional standards. Study findings will be disseminated at an international gastroenterology conference and published in peer-reviewed journals.

Trial registration number: NCT02976805; Pre-results.

Keywords: adult gastroenterology; endoscopy; gastroenterology.

Conflict of interest statement

Competing interests: Pharmascience were not involved in the study protocol and will not have access to study data nor its analysis, interpretation or decision to publish. MSLS has served as a speaker and participated in an advisory board for an unrelated topic for Pharmascience (ie, bile acid diarrhea). DvR has participated in an advisory board and has received research support from Pharmascience.

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    1. Saltzman JR, Cash BD, Pasha SF, et al. Bowel preparation before colonoscopy. Gastrointest Endosc 2015;81:781–94. 10.1016/j.gie.2014.09.048 - DOI - PubMed
    1. Rex DK. Optimal bowel preparation--a practical guide for clinicians. Nat Rev Gastroenterol Hepatol 2014;11:419–25. 10.1038/nrgastro.2014.35 - DOI - PubMed
    1. Johnson DA, Barkun AN, Cohen LB, et al. Optimizing adequacy of bowel cleansing for colonoscopy: recommendations from the U.S. multi-society task force on colorectal cancer. Gastrointest Endosc 2014;80:543–62. 10.1016/j.gie.2014.08.002 - DOI - PubMed
    1. Froehlich F, Wietlisbach V, Gonvers JJ, et al. Impact of colonic cleansing on quality and diagnostic yield of colonoscopy: the European Panel of Appropriateness of Gastrointestinal Endoscopy European multicenter study. Gastrointest Endosc 2005;61:378–84. 10.1016/S0016-5107(04)02776-2 - DOI - PubMed
    1. Clark BT, Rustagi T, Laine L. What level of bowel prep quality requires early repeat colonoscopy: systematic review and meta-analysis of the impact of preparation quality on adenoma detection rate. Am J Gastroenterol 2014;109:1714–23. 10.1038/ajg.2014.232 - DOI - PMC - PubMed

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