EFFECT OF A LOW RESIDUE DIET DURING ONE DAY VERSUS THREE DAYS ON BOWEL CLEANSING, DIET TOLERANCE AND COLONOSCOPY PERFORMANCE: A NON-INFERIORITY RANDOMISED CLINICAL TRIAL

Aims There are no quality studies regarding the optimal length of low residue diet. In order to assess the efficacy and tolerance of a low-residue diet (LRD) during one day versus three days, we designed this trial in participants referred for a screening colonoscopy.

Methods This is a non-inferiority, randomized and masked for the researcher trial conducted in a tertiary care center. We defined a 5% no-inferiority margin, 95% power and 5% a.

Participants followed one or three days of LRD. There were no other differences in the preparation. All of them received Moviprep in split dosing. In case of risk of insufficient preparation, we added 10mg of bisacodyl the day before. Bowel cleansing was evaluated using the Boston Bowel Preparation Scale (BBPS). Inadequate cleansing was defined as a BBPS < 2 in any segment. Diet and preparation tolerance were assessed using a Likert scale.

Results A total of 835 subjects, 420 and 415 in 1 and 3 days diet group respectively, were analyzed. There are no differences in the characteristics nor in the time-lapse from the end of bowel preparation to colonoscopy. One day diet reached a 95.8% of adequate cleansing and three days 95.5%. This makes a difference of -0.3% (-0.31, 0.25 95% CI). Intubation and withdrawal time are similar, 06:10 min and 16:28 min respectively. Regarding tolerance one day obtained a maximum tolerance score in 47,7% of the preparations versus 28,7% in the other group (p< 0,05). There are no differences in Moviprep tolerability (33,2% vs. 27,8% (p>0,05)) nor in adenoma (71.3% vs 71.6%) and polyp detection rates (76.7% vs 74.6%). Only 1 subject experienced an adverse event in 1-day group while 4 in the other.

Conclusions One day of LRD improves tolerability and does not impact bowel cleansing quality nor colonoscopy performance.