Randomized, controlled trial of 2 L polyethylene glycol plus ascorbate components versus sodium phosphate for bowel cleansing prior to colonoscopy for cancer screening

Abstract

Background:

Colonoscopy requires effective bowel preparation for adequate mucosal visualization. Safety and acceptability of bowel preparation are key components in colorectal cancer screening (CRC) populations.

Objective:

To compare the efficacy, safety and acceptability of bowel preparation with polyethylene glycol (PEG), ascorbic acid, sodium ascorbate (ascorbate components), sodium sulfate and electrolytes (PEG+Asc) or sodium phosphate (NaP).

Methods:

Consenting adults undergoing elective out-patient colonoscopy for CRC were randomized to take 2 L PEG+Asc or 90 mL NaP (control) following manufacturer’s instructions. PEG+Asc was taken the evening before and morning of the colonoscopy; NaP was taken the morning and evening before colonoscopy. Participants followed a restricted diet specific to each preparation. Primary endpoint was bowel cleansing success (100% colon mucosa visible) rated by an independent expert panel (all experienced endoscopists) unaware of treatment allocations. Subject reported outcomes about the preparations were elicited. Adverse events were recorded.

Clinical trial registration:

Clinicaltrials.gov: NCT00427089.

Results:

Successful bowel cleansing rate was significantly higher in the PEG+Asc (N = 242) than the NaP (N = 114) group (PEG+Asc 93.4% [95% CI 89.5–96.2] versus NaP 22.8% [15.5–31.6%], p < 0.0001). Subject reported outcomes on acceptability of the two different preparations were not significantly different (p = 0.238). However, taste ratings for PEG+Asc were significantly better versus NaP (mean VAS: 31.2 and 38.1 respectively, p = 0.0111). The proportion of patients prepared to receive the same preparation again was significantly higher in the PEG+Asc group (88.4% vs. 78.1%, p < 0.0001).

Conclusions:

PEG+Asc provided superior bowel cleansing to NaP and was well tolerated. Findings for PEG+Asc are aligned with previous similar studies; however, differences observed in NaP cleansing results, especially for the proximal colon segments, may be due to factors including: differences in demographics and population types and the use of the validated Harefield Cleansing Scale as an assessment tool combined with expert reviews, which may have resulted in conservative cleansing assessments.

Key words::

• Ascorbate components
• Ascorbic acid
• Colon cancer screening
• Colonoscopy
• Polyethylene glycol
• Sodium ascorbate
• Sodium phosphate

Transparency

Declaration of funding

This study was funded by Norgine (protocol #NRL 994-01/2004) and is registered on clinicaltrials.gov (ID NCT00427089). The study sponsor developed the protocol jointly with the coordinating investigator. C.E. acted as coordinating investigator for the Hintertuxer study group and was involved in the study design, study conduct and reviewing the manuscript. M.H. was involved in the study design, study conduct and developing the manuscript. All other authors were involved in data acquisition and approved the final version of the manuscript.

Declaration of financial/other relationships

M.H. has disclosed that he is a medical consultant for Norgine. C.E. has disclosed that Norgine paid fees for lectures and advisory boards. W.F. has disclosed that he is a consultant/advisor for Fresenius Biotech, Norgine, Pfizer, and Vifor Pharma, and has been a speaker for Abbott, Aptalis, Falk, Merck Serono, Novartis, Nycomed, Sanofi Aventis, and Shire. P.L. has disclosed that he is a consultant/advisor for Abbvie, Aptalis, Almirall, Ironwood, Norgine, Pfizer, and Shire, and has been a speaker for Abbvie, Almirall, Falk, Norgine and Shire.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

The authors acknowledge the contributions of Hans-Jürgen Gruss (formerly an employee of Norgine Ltd) in the design and conduct of the study. Study monitoring, project coordination, data management and analysis were performed by IFE Europe GmbH (Essen, Germany), quality assurance was provided by Medical Control Quality Assurance Audit (Leese, Germany), and medical writing assistance was provided by Liz Wager (Sideview, Princes Risborough, UK). These activities were all funded by Norgine Ltd, the manufacturers of Moviprep (2 L PEG+Asc). The Harefield Cleansing Scale is the copyright of the Norgine group of companies 2008–2013.

Previous presentation: Oral presentation at 14th United European Gastroenterology Week, 21–25 October 2006, Berlin, Germany. Ell C et al. Polyethylene glycol with electrolytes and ascorbic acid versus sodium phosphate for bowel cleansing before colonoscopy for cancer screening: a randomized, controlled trial. Endoscopy 2006;38(Suppl II):A18.