Unrestricted vs 3-day low-residue diet for colonoscopy preparation. Results of a feasibility randomized trial.

AIM: To compare the impact of an unrestricted diet with a 3-day low-residue diet before colonoscopy on bowel preparation quality. METHODS: A randomized, multicenter, researcher-blinded, parallel-group feasibility trial was conducted to assess the efficacy of an unrestricted diet versus a 3-day low-residue diet for colonoscopy preparation. Participants, aged 50 to 69, were enrolled in a colorectal cancer screening program with no factors linked to poor bowel cleansing. The Boston Bowel Preparation Scale was used to evaluate colon preparation during intubation and withdrawal. Secondary outcomes included bowel exploration time, adenoma and polyp detection rates, and preparation and diet tolerability. The trial is registered under Clinical Trials (NCT04664543). RESULTS: One hundred and two individuals (mean age 59.3 ± 5.5 years, 40.1% female) were randomly assigned to each diet. All participants in both groups achieved adequate preparation (Boston scores ≥ 2 in each segment). Complete adherence to preparation was observed in the majority of participants in both groups. No significant differences were noted between groups in withdrawal or cecal intubation times, or in adenoma detection rates. The unrestricted diet was better tolerated than the 3-day low-residue diet (82.5% vs. 32.3%). Preparation assessed during intubation was adequate in 82.5% of the unrestricted diet group and in 90.3% of the 3-day low-residue diet group. CONCLUSIONS: It is feasible to test the impact of an unrestricted diet for adequate bowel preparation. Comparable cleansing results were achieved, but the unrestricted diet showed better tolerability.

Restrictive diets are unnecessary for colonoscopy: Non-inferiority randomized trial.

Background and study aims In colonoscopy, preparation is often regarded as the most burdensome part of the intervention. Traditionally, specific diets have been recommended, but the evidence to support this policy is insufficient. The aim of this study was to evaluate the impact of the decision not to follow a restrictive diet on bowel preparation and colonoscopy outcomes. Patients and methods This was a multicenter, controlled, non-inferiority randomized trial with FIT-positive screening colonoscopy. The subjects were assigned to follow the current standard (1-day low residue diet [LRD]) or a liberal diet. The allocation was balanced for the risk of inadequate cleansing using the Dik et al. score. All participants received the same instructions for morning colonoscopy preparation. The primary outcome was the rate of adequate preparations as defined by the Boston Bowel Preparation Scale. Secondary outcomes included tolerability and measures of colonoscopy performance and quality. Results A total of 582 subjects were randomized. Of these, 278 who received the liberal diet and 275 who received the 1-day LRD were included in the intent-to-treat analysis. Non-inferiority was demonstrated with adequate preparation rates of 97.8% in the 1-day LRD and 96.4% in the liberal diet group. Tolerability was higher with the liberal diet (94.7% vs. 83.2%). No differences were found with respect to cecal intubation time, aspirated volume, or length of the examination. Global and right colon average adenoma detection rates per colonoscopy were similar. Conclusions The liberal diet was non-inferior to the 1-day LRD, and increased tolerability. Colonoscopy performance and quality were not affected. (NCT05032794).