The safety and effects of high- and low-volume polyethylene glycol bowel preparation methods before colonoscopy on bowel cleanliness: a systematic review and meta-analysis

Background: Although both high- and low-volume polyethylene glycol (PEG) are widely used in intestinal preparation before colonoscopy, there is still controversy over the superiority of their cleaning effects. This meta-analysis sought to explore the safety and effects of high-volume PEG solution and low-volume PEG mixed solution on intestinal cleanliness before colonoscopy. Methods: The PubMed, EMBASE, and Cochrane Library databases were searched to retrieve relevant articles on the effects of high- and low-volume PEG mixture solutions on intestinal cleanliness from the inception of the databases to October 15, 2022. Two independent researchers screened the literature according to the predetermined inclusion and exclusion criteria, and extracted the required data separately. A bias risk assessment was conducted for each study using the relevant tools in the Cochrane Handbook. The included data were subjected to a meta-analysis using R 4.2.1 software. Results: This article includes a total of 15 studies involving a total of 5,847 patients. There was no difference in the cleanliness score, qualified rate of intestinal cleanliness and patient compliance between the high- and low-volume group. The patients in the low-volume PEG mixed solution group had a higher repeat willingness bowel cleansing rate than those in the high-volume PEG group [ risk ratio (RR) =0.71, 95% confidence interval (CI): 0.62-0.82, P<0.01]. Compared with the low-volume group, the incidence of adverse reactions such as nausea, vomiting, and abdominal pain increased in the high-volume group (RR =1.38, 95% CI: 1.22-1.56, P<0.01; RR =1.79, 95% CI: 1.41-2.27, P<0.01; RR =1.05, 95% CI: 1.01-1.08, P<0.01). Conclusions: In the pre-colonoscopy preparation method for patients, although the high-volume PEG and low-volume PEG mixed regimen have similar effects on intestinal cleanliness, the low-volume mixed regimen has a higher willingness to repeat and a lower incidence of adverse reactions. In clinical practice, considering patient compliance and safety, a low-volume mixed regimen may be a more optimal option.