3-day vs. 1-day low residue diet influence in colonoscopy preparation and patient tolerability

Conditions: Colon Disease; Colonic Neoplasms

Summary: colonoscopy is one of the most common methods for the diagnosis and treatment of lower gastrointestinal tract diseases and provides a unique opportunity to identify early neoplastic lesions. adequate bowel preparation is important for optimal colonoscopy. new bowel-cleansing regimens, study of patient-related risk factors to fail a proper preparation and diet adaptations have been studied recently. a low residue diet is the standard in the day before the colonoscopy. some endoscopists prescribe this dietary plan for a 3-day period prior to the exam, although no study compared the recommended 1-day versus 3-day diet regime, or the influence in bowel preparation results. the aim of this project is to determine if the use of a 3-day low residue diet improves bowel preparations results and the influence in patient tolerability and adherence.

a. study type: prospective, randomized, single-blinded trial: i. prospective inclusion of ambulatory patients; ii. randomization by computer generated tables; iii. allocation concealment by sealed, opaque envelopes; iv. patient not blinded to diet; v. endoscopist blinded to the diet followed by each patient. b. patient selection: consecutive series of patients scheduled for total colonoscopy; exclusion criteria: inpatients, sedation, urgent procedures, colonoscopies not intended to reach the caecum, patient with previous partial colectomy. c. sample size: i. 412 individuals; 2 groups of 206 patients ii. primary goal: to achieve a reduction from 15 to 5% of inappropriate preparation result; the boston bowel preparation scale (bbps) will be used as grading system. inappropriate is defined as total bbps \< 6 or \< 2 in any segment. the chosen scale is the most systematically validated and appropriate for the clinical setting. iii.both groups, from a community-based outpatient ambulatory center, used the same split dose regimen with polyethylene glycol (peg).patients were instructed to drink 3 l of peg preparation on the afternoon of the day prior to the exam and 1 l four hours before the scheduled exam time. all the exams scheduled for morning period. assuming a normal distribution, a power of 90% and a type i error of 0.05, the calculated sample size for each group was 188; allowing a 10% dropout rate, the sample size is 206 per group (412 patients overall); groups: group a: 3-day low residue diet + split dose preparation; group b: 1-day low residue diet + split dose preparation d. endoscopist: exams to be conduct by 5 board-certified gastroenterologists and 2 supervised fellows in training; all physicians were trained in the use of bbps by online training available at http://cori.org/bbps/, and have been using the bbps for at least 3 months. e. data collection methods: form sheet filled by the endoscopist and patient opinion regarding the assigned bowel preparation protocol. f. analyzed variables: i. primary outcome: bbps score ii. secondary outcome: patient assessment of tolerance and acceptance of the preparation and diet iii. tertiary outcome: polyp detection rate (pdr), polyp location, size and configuration; adenoma detection rate (adr), cecum intubation rate iv. other variables and patients characteristics (age, gender, chronic medication, risk factors for inappropriate preparation), withdrawal time. g. statistical analysis: t-test for groups comparing quantitative variables with normal distribution (primary outcome); qui square test for groups comparing proportions (secondary and tertiary outcomes)

Eligibility criteria:
inclusion criteria: * consecutive series of patients scheduled for total colonoscopy * signed informed consent exclusion criteria: * inpatients * sedation * urgent procedures * colonoscopies not intended to reach the caecum * patient with previous partial colectomy.

Keywords: randomized controlled trial colonoscopy colon disease low residue diet colon preparation