Randomized Controlled Trial in Patients With Failed Bowel Preparation

Randomized Controlled Trial in Patients With Failed Bowel Preparation

Douglas K. Rex, MD, MASGE, reviewing Sey MSL, et al. Clin Gastroenterol Hepatol 2021 Jul 9.

When a patient is compliant with bowel preparation instructions, but the preparation is inadequate, there are little data from controlled trials to guide the bowel preparation prescription for a repeat colonoscopy. Most practitioners switch to a different regimen or repeat the original preparation but add more laxatives. 

In a 4-center, Canadian randomized trial, patients who previously followed instructions but failed bowel preparation were randomized to receive 15 mg of bisacodyl followed by 4 L of polyethylene glycol (PEG) the day before colonoscopy plus 2 L of PEG the morning of colonoscopy versus 15 mg of bisacodyl followed by 2 L of PEG the day before and 2 L of PEG the morning of colonoscopy.

The additional 2 L of PEG did not improve the rate of adequate preparation, which was 91.2% with 4 L total and 87.6% with 6 L total (P=.44). The ability to consume 100% of PEG was 88.2% with 4 L versus 74.7% with 6 L (P=.02). Willingness to repeat the preparation was higher among patients who consumed 4 L (91.2%) versus 6 L (66.2%) (P<.001).

Douglas K. Rex, MD, FASGE

COMMENT

This result is unexpected because it shows that adding 2 L of PEG had no impact on efficacy and only reduced tolerability. This result is important, given the few controlled data available for managing inadequate preparation. We need more studies, but these data suggest that adding laxative pills or other low-volume laxatives is the best approach if the base regimen for the repeat colonoscopy is 4 L of PEG.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.

CITATION(S)

Sey MSL, Von Renteln D, Sultanian R, et al. A multi-centre randomized controlled trial comparing two bowel cleansing regimens for colonoscopy after failed bowel preparation. Clin Gastroenterol Hepatol 2021 Jul 9. (Epub ahead of print) (https://doi.org/10.1016/j.cgh.2021.07.015)

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