Comparison between different colon cleansing products for screening colonoscopy. A noninferiority trial in population-based screening programs in Italy.

BACKGROUND AND STUDY AIMS: The high volume and poor palatability of 4 L of polyethylene glycol (PEG)-based bowel cleansing preparation required before a colonoscopy represent a major obstacle for patients. The aim of this study was to compare two low volume PEG-based preparations with standard 4 L PEG in individuals with a positive fecal immunochemical test (FIT) within organized screening programs in Italy. PATIENTS AND METHODS: A total of 3660 patients with a positive FIT result were randomized to receive, in a split-dose regimen, 4 L PEG or 2 L PEG plus ascorbate (PEG-A) or 2 L PEG with citrate and simethicone plus bisacodyl (PEG-CS). The noninferiority of the low volume preparations vs. 4 L PEG was tested through the difference in proportions of adequate cleansing. RESULTS: A total of 2802 patients were included in the study. Adequate bowel cleansing was achieved in 868 of 926 cases (93.7 %) in the 4 L PEG group, in 872 out of 911 cases in the PEG-A group (95.7 %, difference in proportions  + 1.9 %, 95 % confidence interval [CI]  - 0.1 to 3.9), and in 862 out of 921 cases in the PEG-CS group (93.6 %, difference in proportions  - 0.2 %, 95 %CI  - 2.4 to 2.0). Bowel cleansing was adequate in 95.5 % of cases when the preparation-to-colonoscopy interval was between 120 and 239 minutes, whereas it dropped to 83.3 % with longer intervals. Better cleansing was observed in patients with regular bowel movements (95.6 %) compared with those with diarrhea (92.4 %) or constipation (90.8 %). CONCLUSION: Low volume PEG-based preparations administered in a split-dose regimen guarantee noninferior bowel cleansing compared with 4 L PEG. Constipated patients require a personalized preparation. TRIAL REGISTRATION: EudraCT 2012 - 003958 - 82.