Large-volume regimen preferred after previous poor bowel preparation

Last Updated: 2017-04-05

By Scott Baltic

NEW YORK (Reuters Health) - An intensified bowel prep regimen that includes split-dose large-volume polyethylene glycol (PEG) is superior to a similar low-volume PEG (plus ascorbic acid) regimen in patients who had inadequate bowel preparation for a previous colonoscopy.

In their report online March 14 in the American Journal of Gastroenterology, the Spanish researchers cited data showing that previous poor bowel preparation is the primary risk factor for inadequate bowel preparation at the next colonoscopy.

They also point out that while guidelines for bowel cleansing favor large-volume preparations using PEG, some recent studies have suggested that a low-volume preparation achieves similar efficacy, at least in a non-selected population.

All 256 patients underwent intensive preparation starting with a three-day low-residue diet, then two tablets (10mg) of bisacodyl the night before starting the actual bowel-cleansing regimen.

Patients were randomized 1:1 to receive either a low-volume preparation (2 L of water with PEG and ascorbic acid, plus 1 L of just water) or a large-volume preparation (4 L of water with PEG).

The effectiveness of bowel cleansing was rated according to the Boston Bowel Preparation Scale by two endoscopists who were masked to the patient allocation group.

The group that received the large-volume regimen had a significantly higher percentage of patients with adequate bowel preparation (81.1% versus 67.4%). The difference between the groups was so clear that the study was terminated after an interim analysis.

Inadequate bowel preparation occurs on average about 25% of the time, which “becomes a huge issue from a cost and quality standpoint,” said Dr. David A. Johnson of the Eastern Virginia Medical School, Norfolk, who was not involved in the study.

The current goal is to drive that below 15%, added Dr. Johnson, who is a member of the U.S. Multi-Society Task Force on Colorectal Cancer.

Inadequate bowel preparation reflects not just on the patient, but on the physician and the system, he said in a phone interview, adding that physicians may soon be held accountable for the success of bowel preparation.

Dr. Johnson noted that one of the study’s limitations was a lack of validation of compliance with the low-residue diet, but was also impressed that the study closed early.

The study’s corresponding author, Dr. Antonio Z. Gimeno-Garcia at Hospital Universitario de Canarias, did not reply to a request for comment.

SOURCE: http://go.nature.com/2oJLX3g

Am J Gastroenterol 2017.