Efficacy of 1 L polyethylene glycol plus ascorbate versus 4 L polyethylene glycol in split-dose for colonoscopy cleansing in out and inpatient: A multicentre, randomized trial (OVER 2019)

Background and aims: Adequate bowel cleansing is essential for colonoscopy quality. A novel 1 L polyethylene glycol plus ascorbate (1 L PEG+ASC) solution has been recently introduced. Nevertheless, the efficacy of 1 L PEG+ASC as compared to that of high-volume bowel preparation in both inpatients and outpatients is still unclear. Patients and methods: This single-blinded, non-inferiority study randomized patients undergoing colonoscopy to receive split-dose 1 L PEG+ASC or 4 L PEG. The primary endpoint was the overall cleansing success. Secondary endpoints were excellent cleansing and high-quality cleansing of the right colon, as well as lesions detection rate, patient compliance, tolerability and safety. Results: Overall, 478 patients were randomized to 1 L PEG+ASC (N = 236) or 4 L PEG (N = 242). The 1 L PEG+ASC showed higher cleansing success rate (91.8% vs 83.6%; P=0.01) and a high-quality cleansing of the right colon (52.3% and 38.5%; P=0.004) compared to 4 L PEG. Moreover, 1 L PEG+ASC achieved a higher cleansing success in out-patients (96.3%% vs 88.6%; P=0.018), and a similar success rate in the in-patients (84.7% vs 76.7%; P=0.18). Adenoma detection rate, tolerability and incidence of adverse events were comparable between preparations. Conclusions: The 1 L PEG+ASC showed higher efficacy in achieving adequate colon cleansing compared with 4 L PEG, particularly in the right colon. No differences in the tolerability and safety were detected.