1L-PEG-ASC Improves Colonoscopy Cleansing vs Other Preparations

Originally introduced to improve patients’ experience in colonoscopy, 1-L PEG-ASC outperforms traditional bowel preparations in bowel cleansing outcomes.

One-liter (1L) polyethylene glycol (PEG) plus ascorbate (ASC) for colonoscopy preparation is associated with greater cleansing success compared with other preparations, but it has a worse safety profile. These study findings were published in Digestive and Liver Disease.

Researchers in Italy conducted a systemic review and meta-analysis of publication databases through July 2022 for studies evaluating the safety and efficacy of various colonoscopy preparation strategies. A total of 9 studies were included in the analysis.

Most studies used split-dosing interventions (n=8) and 1 study used a day-before regimen. All studies evaluated a 1L-PEG-ASC preparation (n=11) compared with a 2-L PEG-ASC preparation (n=5), 4-L PEG-ASC preparation (n=1), trisulfate preparation (n=1), sodium picosulfate/magnesium citrate (SPMC) preparation (n=1), or SPMC plus PEG preparation (n=1).

Sample sizes ranged from 44 to 320 patients in the studies. The study participants had a mean age of 45.6 to 70.9 years and the mean body mass index (BMI) range was 24.1 kg/m2 to 29.8 kg/m2.

Overall, 1L-PEG-ASC was favored over other preparations for cleansing success (odds ratio [OR], 1.50; 95% CI, 1.25-1.81; I2, 0%; P <.01) and high-quality cleansing of the right colon (OR, 1.67; 95% CI, 1.21-2.31; I2, 43%; P <.01), but not for the adenoma detection rate (OR, 1.02; 95% CI, 0.87-1.20; I2, 0%; P =.79).

Similar trends were reported among only the studies with a split-dose intervention or with the 2-L PEG-ASC as the comparator.

1-L PEG-ASC was associated with higher overall CS and right-colon HQC rates than the other bowel preparations. Meanwhile, the ADR was comparable between them.

The 1L-PEG-ASC preparation was associated with more patient-reported adverse events (OR, 1.51; 95% CI, 1.23-1.84; I2, 0%; P <.01), a higher adverse event rate (OR, 1.33; 95% CI, 1.11-1.58; I2, 71%; P <.01), more vomiting (OR, 2.22; 95% CI, 1.60-3.07; I2, 8%; P <.01), and nausea (OR, 1.45; 95% CI, 1.24-1.70; I2, 0%; P <.01) compared with other preparations.

In subgroup analyses, significant effects of 4-liter PEG control (β, -0.364; P =.004), publication year (β, -0.175; P =.001), sample size in the 1L-PEG-ASC treatment arm (β, 0.001; P =.028), sample size in the comparator preparation arm (β, 0.002; P =.025), and SPMC control (β, 0.474; P =.044) had significant effects on the adverse event outcome.

The results of this study may have been limited by the different comparator groups and the observed heterogeneity.

The study authors state, “In conclusion, 1-L PEG-ASC was associated with higher overall CS and right-colon HQC rates than the other bowel preparations. Meanwhile, the ADR was comparable between them.”

Disclosure: An author declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Maida M, Ventimiglia M, Facciorusso A, Vitello A, Sinagra E, Marasco G. Effectiveness and safety of 1-L PEG-ASC versus other bowel preparations for colonoscopy: A meta-analysis of nine randomized clinical trials. Dig Liver Dis. 2022;S1590-8658(22)00788-5. doi:10.1016/j.dld.2022.11.010