3-day vs. 1-day Low Residue Diet Influence in Colonoscopy Preparation and Patient Tolerability

Study Overview
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Brief Summary
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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.

Detailed Description
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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)

Official Title
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A 3-day Versus 1-day Low Residue Diet to Improve Colonoscopy Preparation Result and Patient Tolerability: A Prospective, Randomized, Single-blinded, Controlled Trial

Conditions
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Colon Disease, Colonic Neoplasms

Intervention / Treatment
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* Other: 3 day low residue diet prior to the colonoscopy
* Other: 1 day low residue diet prior to the colonoscopy


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 3-day low residue diet<br>Group A - 3 day low residue diet prior to the colonoscopy | Other: 3 day low residue diet prior to the colonoscopy<br>* 3 day low residue diet prior to the colonoscopy<br>|
| Placebo Comparator: 1-day low residue diet<br>Group B - 1 day low residue diet prior to the colonoscopy | Other: 1 day low residue diet prior to the colonoscopy<br>* 3 day low residue diet prior to the colonoscopy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Score of mucosal visualization | Using Boston Bowel Preparation Scale during the exam | 1 day (during colonoscopy) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient assessment of diet protocol | Patient assessment, by written questionnaire, of tolerance and acceptance of diet protocol. | 1 day (the day of the exam) | 
| Polyp detection rate, location and configuration | One of the quality indicators for colonoscopy is polyp detection rate, which is defined as the percentage of colonoscopies with a detection of at least one polyp. At the same time the endoscopist will assign the colonic location of the polyp (ascendent, transverse, descendent). (PDR to be presented as %; Location to be discriminated in the endoscopist report). | 1 day (during colonoscopy) | 
| Adenoma Detection Rate | Adenoma detection rate (ADR) is the one of the strongest quality indicators for colonoscopy. This rate represents the percentage of colonoscopies with at least one adenoma identified. (to be presented as %) | Within 30 days from colonoscopy date | 
| Cecum intubation rate | Defined as colonoscopy quality indicator the photo documentation of cecum, in at least 95% of the colonoscopies. Photo documentation of the cecum is a mark for effective total colonoscopy. (to presented as %) | 1 day (during colonoscopy) | 
| Withdrawal time | In a negative colonoscopy (no polyp identification) is defined that the withdrawal time should be at least 6 minutes for proper and safe colonic mucosa evaluation. (to be presented in minutes) | 1 day (during colonoscopy) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Colonoscopy, Randomized controlled trial, Colon Disease, Low residue diet, Colon preparation