Send to

Choose Destination
Am J Gastroenterol. 2017 Jun;112(6):951-958. doi: 10.1038/ajg.2017.53. Epub 2017 Mar 14.

Comparison of Two Intensive Bowel Cleansing Regimens in Patients With Previous Poor Bowel Preparation: A Randomized Controlled Study.

Author information

Departamento de Medicina Interna, Servicio de Gastroenterología, Hospital Universitario de Canarias, Instituto Universitario de Tecnologías Biomédicas (ITB) &Centro de Investigación Biomédica de Canarias (CIBICAN), Universidad de La Laguna, La Laguna, Spain.
Unidad de Ensayos Clínicos, Hospital Universitario de Canarias.
Unidad de Investigación, Hospital Universitario de Canarias.



Inadequate bowel cleansing is a major burden for endoscopy units. The aim of this study was to compare two intensive bowel cleansing regimens in patients with previous colonoscopy with inadequate bowel preparation.


Patients with inadequate cleansing at index colonoscopy were randomized to 4-L split-dose polyethylene-glycol (PEG) regimen vs. 2-L split-dose PEG plus ascorbic acid (PEG+Asc) regimen. All individuals underwent a 3-day low-residue diet and received 10 mg of bisacodyl, the day before colonoscopy. Cleansing was considered to be adequate if the Boston Bowel Preparation Scale scored ≥2 at each colonic segment. A non-inferiority analysis was performed to demonstrate that colonic cleansing with 2-L PEG+Asc was not inferior to 4-l PEG, considering a non-inferiority margin of 10%.


Adequate bowel cleansing was significantly higher in patients assigned to 4-L PEG regimen (n=127) vs. those randomized to 2-L PEG+Asc regimen (n=129) by intention-to-treat analysis (81.1 vs. 67.4%, odds ratio (OR) 2.07, 95% confidence interval (CI) (1.163-3.689)) and by per-protocol analysis (86.6 vs. 71.7%, OR: 2.55, 95% CI: (1.316-4.922)). The study was terminated for futility after the interim analysis, because the 95% CI of the difference of proportions was 3.13-24.27% in the intention-to-treat analysis and 3.33-26.47% in the per-protocol analysis, confirming the superiority of 4-L PEG preparation.


After 3-day low-residue diet and oral bisacodyl before colonoscopy, colon cleansing with 4-L split-dose PEG was superior to 2-L split-dose PEG+Asc in patients with previous inadequate cleansing. (EUDRACT: 2013-002506-31, NCT02073552).

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Nature Publishing Group
Loading ...
Support Center