The Bowel CLEANsing National Initiative: High-Volume Split-Dose Vs Low-Volume Split-Dose Polyethylene Glycol Preparations: A Randomized Controlled Trial.

BACKGROUND & AIMS: The aim of this study was to compare high-volume polyethylene glycol (PEG) with low-volume PEG with bisacodyl split-dosing regimens. METHODS: Adult outpatients in 10 Canadian tertiary hospitals were randomized, stratified by morning or afternoon colonoscopy, to high-volume split-dose PEG (2 L + 2 L) (High-SD) or low volume (1 L + 1 L) + bisacodyl (15 mg) PEG (Low-SD), with a second randomization to liquid or low-residue diets. The primary end point, using noninferiority hypothesis testing, was adequate bowel cleansing (Boston Bowel Preparation Scale total score of ≥6, with each of 3 colonic segments subscores ≥2). Secondary objectives were willingness to repeat the preparation, withdrawal time, cecal intubation, and polyp detection rates. RESULTS: Over 29 months, 2314 subjects were randomized to High-SD (N = 1157) or Low-SD (N = 1157) (mean age, 56.2 ± 13.4 y; 52.1% women). Colonoscopy indications were 38.2% diagnostic, 36.8% screening, and 25.0% surveillance, with no between-group imbalances in patient characteristics. Low-SD satisfied noninferiority criteria vs High-SD for adequate bowel cleanliness with only marginally inferior results (90.1% vs 88.1%; P = .02; difference, 2.0%; 95% CI [0.0%; 4.5%]). High-SD was associated with lower willingness to repeat (66.9% vs 91.9%; P < .01), was less well tolerated (7.3 ± 2.3 vs 8.1 ± 1.9; P < .01), causing more symptoms. No differences in procedural outcomes were noted except for more frequent cecal intubation rates after High-SD (97.4% vs 95.6%; P = .02). Among the High-SD group, adequate bowel preparation was greater after a clear liquid diet (93.6% vs 87.9%; P < .01), a finding not seen in the Low-SD group. CONCLUSIONS: Low-SD is noninferior to High-SD in providing adequate bowel preparation. Low-SD results in fewer symptoms, with greater willingness to repeat and tolerability. The overall impact of diet was modest.The study was approved by the research ethic boards from all sites and was registered at ClinicalTrials.gov (NCT02547571).

The Bowel CLEANsing National Initiative: A Low-Volume Same-Day Polyethylene Glycol (PEG) Preparation vs Low-Volume Split-Dose PEG With Bisacodyl or High-Volume Split-Dose PEG Preparations-A Randomized Controlled Trial.

INTRODUCTION: Bowel cleanliness has been shown to be superior with split-dose vs nonsplit preparations; we aimed to directly assess the poorly characterized comparative efficacies of split-dose vs same-day polyethylene glycol (PEG) regimens. METHODS: In this study, one of a series of randomized trials performed across 10 Canadian endoscopy units, patients undergoing colonoscopies between 10:30 and 16:30 were allocated to PEG low-volume same-day (15 mg bisacodyl the day before, 2 L the morning of the procedure), low-volume split-dose (15 mg bisacodyl the day before, 1 L + 1 L), or high-volume split-dose (2 L + 2 L). Coprimary endpoints were adequate bowel cleansing based on the Boston Bowel Preparation Scale using in turn different threshold cutoffs. RESULTS: Overall, 1,750 subjects were randomized equally across the 3 groups, with no differences in adequate bowel cleanliness rates (low-volume same-day, 90.5%; high-volume split-dose, 92.2%; P = 0.34; and low-volume split-dose, 87.9%; P = 0.17) for the Boston Bowel Preparation Scale ≥6 and 2 for each segment. Willingness to repeat the preparation was not significantly different between low-volume same-day (91.0%) and low-volume split-dose (92.5%; P = 0.40) but was greater than the high-volume split-dose (68.9%; P < 0.01). No significant differences were noted for withdrawal time, cecal intubation, or polyp detection rates. DISCUSSION: In this large randomized trial of PEG regimens, low-volume same-day resulted in similar bowel cleanliness compared with high-volume or low-volume split-dosing. Willingness to repeat and tolerability were superior with low-volume same-day compared with high-volume split-dose and similar to low-volume split-dose.