Split-dose 1 L polyethylene glycol (PEG) with ascorbate is non-inferior to split-dose PEG with sodium picosulfate and magnesium citrate with similar tolerability: a randomized study

Background and Aim: Post-marketing studies comparing low-volume polyethylene glycol (PEG)-based regimens are limited. This randomized study aimed to compare the efficacy and tolerability of a novel 1-L low-volume PEG-based preparation: 1 L PEG+Asc (PEG3350, sodium ascorbate, sodium sulfate, ascorbic acid, sodium chloride, and potassium chloride) with PEG+SPMC (PEG3350, sodium chloride, potassium chloride and sodium sulfate, sodium picosulfate, magnesium oxide, citric acid, and aspartame), prior to routine colonoscopy at an Australian tertiary referral center. Methods: Outpatients undergoing colonoscopy were randomized to receive either split-dose 1 L PEG+Asc or split-dose PEG+SPMC. Bowel preparation quality using the Boston Bowel Preparation Scale (BPPS), modified Aronchick scores, procedure time, cecal intubation, and adenoma detection rates were recorded. Patient compliance and tolerability were captured using a standardized questionnaire. Results: A total of 173 patients were randomized, of whom 164 completed the study and were allocated to 1 L PEG+Asc (n = 82) or PEG+SPMC (n = 82). Non-inferiority of 1 L PEG+Asc was demonstrated with 89% achieving successful preparation (total BPPS ≥6 and each sub-score ≥2) compared with 85.4% in the PEG+SPMC group, resulting in an estimated difference of 3.7% (95% CI −6.6% to 13.9%). The median BBPS was non-inferior in all colonic segments with 1 L PEG+Asc (BBPS 3 [interquartile range 2–3]) vs PEG+SPMC (BBPS 2 [interquartile range 2–3]). More 1 L PEG+Asc patients reported moderate to severe nausea (P = 0.028), but overall tolerability was similar. Conclusions: The quality of bowel preparation achieved with 1 L PEG+Asc is non-inferior to that with PEG+SPMC, with similar tolerability outcomes. Further studies are required in patients at risk of suboptimal bowel preparation.