Efficacy and Safety of 1-L Polyethylene Glycol With Low Ascorbic Acid for Bowel Preparation: A Randomized Clinical Trial.
Ji Eun Baek, Hyo Suk Kim, Sung Hoon Jung et al.
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In 30 seconds
This multicenter, investigator-blinded, three-arm randomized noninferiority trial compared reduced-ascorbic-acid 1-L polyethylene glycol (PEG) with standard 1-L and 2-L PEG plus ascorbic acid in low-risk adults undergoing colonoscopy. Among 242 per-protocol participants, successful cleansing by the Harefield scale occurred in 92.7%, 100.0%, and 98.7%, respectively. The reduced-ascorbic-acid regimen met the trial’s noninferiority criteria versus both comparators, although the observed cleansing rate was numerically lower. Tolerability and adverse-event rates were comparable, and no electrolyte disturbances or renal events were observed.
Key findings
- Harefield-scale cleansing success was 92.7% with low-ascorbic-acid 1-L PEG, 100.0% with standard 1-L PEG, and 98.7% with 2-L PEG.
- The low-ascorbic-acid regimen met noninferiority criteria versus standard 1-L PEG; risk difference, -7.3%; 97.5% CI, -13.0 to -1.6.
- BBPS-defined success, adenoma detection rates, gastric fluid volumes, and willingness to repeat were similar across groups.
- Adverse-event rates were comparable, with no electrolyte disturbances or renal events observed.
Why it matters
Bowel preparation must balance adequate cleansing with tolerability and safety. These trial findings suggest that reducing the ascorbic acid dose in a 1-L PEG regimen can retain noninferior cleansing efficacy in low-risk adults, without an observed increase in adverse events. The numerical difference in Harefield-scale success and the study population remain relevant when interpreting the result.
What to keep in mind
The trial enrolled low-risk adults, so its findings may not apply to higher-risk populations. The reported efficacy analysis included 242 per-protocol participants.