Comparative Efficacy and Safety of 0.8-L Versus 2-L Polyethylene Glycol-Ascorbic Acid Solutions in Colonoscopy Preparation: A Prospective, Multicenter, Randomized, Controlled Trial

Background and Aim: High-volume polyethylene glycol (PEG) solutions are associated with low patient compliance, whereas low-volume alternatives pose higher risks of adverse events. We compared a new 0.8-L PEG–ascorbic acid solution containing simethicone to a 2-L PEG–ascorbic acid solution. Methods: In this prospective, investigator-blinded study, 137 outpatients from five centers were randomized into three groups: Group A (0.8-L PEG–ascorbic acid with a split-dose regimen), Group B (0.8-L PEG–ascorbic acid on the same day as the colonoscopy), and Group C (2-L PEG–ascorbic acid with a split-dose regimen). The primary outcome was the cleansing efficacy, assessed using the Harefield Cleansing Scale (HCS). Secondary outcomes included bubble score, polyp and adenoma detection rates, patient satisfaction, tolerability, and safety. Results: All groups achieved 100% successful preparation (HCS grades A and B). Group B had a higher HCS grade in the ascending colon than Group C (3.2 vs. 3.0, p = 0.01). Groups A and B showed better bubble scores than Group C (p < 0.0001). Polyp and adenoma detection rates were similar across the groups. Group B demonstrated the highest satisfaction score (139.1 ± 76.7), followed by Group A (129.8 ± 64.9) and Group C (125.6 ± 60.0), with no significant differences. The tolerability and safety parameters were similar between the groups. Conclusions: The novel 0.8-L PEG–ascorbic acid solution was effective, safe, and highly tolerable, showing noninferiority to the 2-L PEG–ascorbic acid solution. The same-day regimen showed a tendency toward better cleansing efficacy in the ascending colon and higher patient satisfaction.