Improving the tolerability and safety of 1-L polyethylene glycol plus low-dose ascorbic acid for bowel preparation in a healthy population: a randomized multicenter clinical trial

Background and Aims One-liter polyethylene glycol plus ascorbic acid (PEG-ASC) improves patient tolerability, but some patients still show low tolerability to a relatively high content of ASC. This study aimed to improve the tolerability and safety of 1-L PEG with low-dose ASC in comparison with standard 1-L and 2-L PEG-ASC. Methods This was a randomized, controlled, double-blinded, multicenter, noninferiority trial involving 215 healthy adults who underwent colonoscopy from June 2020 to January 2021. Efficacy, tolerability, and safety were compared among 1-L PEG with low-dose ASC (50% lower ASC concentration in group A and 25% lower ASC concentration in groups B and C) and standard 1-L and 2-L PEG-ASC with all split regimens. Results One-liter PEG with low-dose ASC (groups A-C) had similar bowel cleansing efficacies according to the Harefield Cleansing Scale and Boston Bowel Preparation Scale, without negative clinical performance, compared with standard 1-L and 2-L PEG-ASC preparation (all P > .1). One-liter PEG with low-dose ASC had better tolerability compared with 2-L PEG-ASC and less residual fluid retention in the stomach compared with 1-L PEG-ASC, proportional to the amount of ASC. No significant differences were found in the incidences of overall adverse events, mild adverse events, or death or in the occurrence of gastroduodenal erosion or ulcer in upper endoscopy. Conclusions One-liter PEG with low-dose ASC (25%-50% reduction in dose) for bowel cleansing showed similar efficacy and safety compared with standard 1-L or 2-L PEG-ASC, better tolerability compared with 2-L PEG-ASC, and less residual gastric fluid retention compared with standard 1-L PEG-ASC. (Clinical trial registration number: KCT0005490.) One-liter polyethylene glycol plus ascorbic acid (PEG-ASC) improves patient tolerability, but some patients still show low tolerability to a relatively high content of ASC. This study aimed to improve the tolerability and safety of 1-L PEG with low-dose ASC in comparison with standard 1-L and 2-L PEG-ASC. This was a randomized, controlled, double-blinded, multicenter, noninferiority trial involving 215 healthy adults who underwent colonoscopy from June 2020 to January 2021. Efficacy, tolerability, and safety were compared among 1-L PEG with low-dose ASC (50% lower ASC concentration in group A and 25% lower ASC concentration in groups B and C) and standard 1-L and 2-L PEG-ASC with all split regimens. One-liter PEG with low-dose ASC (groups A-C) had similar bowel cleansing efficacies according to the Harefield Cleansing Scale and Boston Bowel Preparation Scale, without negative clinical performance, compared with standard 1-L and 2-L PEG-ASC preparation (all P > .1). One-liter PEG with low-dose ASC had better tolerability compared with 2-L PEG-ASC and less residual fluid retention in the stomach compared with 1-L PEG-ASC, proportional to the amount of ASC. No significant differences were found in the incidences of overall adverse events, mild adverse events, or death or in the occurrence of gastroduodenal erosion or ulcer in upper endoscopy. One-liter PEG with low-dose ASC (25%-50% reduction in dose) for bowel cleansing showed similar efficacy and safety compared with standard 1-L or 2-L PEG-ASC, better tolerability compared with 2-L PEG-ASC, and less residual gastric fluid retention compared with standard 1-L PEG-ASC. (Clinical trial registration number: KCT0005490.)