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Impact of Low Fiber Diet on Colonic Cleansing Quality (DIETPREP)

Not Applicable
Completed
Conditions
Cleansing Quality of the Colon
Interventions
Other: One-day Low fiber diet
Other: Three-day low fiber diet
Drug: Polyethylene Glycol plus ascorbic acid
Registration Number
NCT03247452
Lead Sponsor
Hospital Universitario de Canarias
Brief Summary

This is a single center randomized controlled trial to compare bowel cleansing for outpatient colonoscopy in two groups of participants: one group will receive instructions of one-day structured low fiber diet whilst the other group will receive three-day low fiber diet.

Both groups will receive the same bowel cleansing solution (polyethylene glycol plus ascorbic acid). Bowel cleansing will be assessed according the Boston Bowel Preparation Scale.

Detailed Description

It is well-known that low fiber diet before colonoscopy is at least equivalent to liquid diet. However, tolerance is better with low fiber diet. There is no current evidence whether the number of days on low fiber diet before colonoscopy have any influence on bowel cleansing quality.

This is the first controlled, randomized trial to compare bowel cleansing by using two different protocols: one day low fiber diet versus three day low fiber diet.

A researcher will offer to participate in the study to scheduled for outpatient colonoscopy, who meet all the inclusion criteria and none of the exclusion criteria. The researchers will explain the purpose of the study and will ask to sign the informed consent. They will give verbal and written information on the diet and the bowel cleansing solution to be taken. Thus, according to the allocation group, participants must comply with a low fiber diet the previous day of the examination or 3 days prior to the examination. In both cases, patients will take a liquid diet the night before.

Patients from both groups will receive low volume preparation with 1 L of polyethylene glycol plus ascorbic acid 12 hours prior to the appointment of the colonoscopy and 1 L of PEG with ascorbic acid 5 hours before the appointment for colonoscopy.

Patients must complete a baseline questionnaire at the inclusion visit and another questionnaire at the colonoscopy visit.

The hypothesis of the study is that in non-selected population, a 3-day low fiber diet before colonoscopy is superior to 1-day low fiber diet in achieving an acceptable bowel cleansing assessed by a validated scale (Boston Bowel Preparation Score).

For the present study, a 10% improvement in the quality of colonic cleaning was hypothesized in the group of patients receiving 3 day low fiber diet regimen. Taking into account a power of 80%, alpha error of 5% and losses of 15% will require 202 patients per group.

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
404
Inclusion Criteria
  • Age ≥ 18 years
Exclusion Criteria
  • Patients with previous colon surgery
  • Last colonoscopy with poor bowel preparation
  • Ileus, intestinal obstruction, megacolon
  • Poorly controlled hypertension (HTAS> 180 HTAD> 100)
  • Terminal renal failure (pre-dialysis or dialysis)
  • Congestive heart failure (NYHA III-IV)
  • Acute liver failure
  • Severe psychiatric illness
  • Dementia with difficulty in the intake of the preparation
  • Pregnancy or breastfeeding
  • Phenylketonuria
  • Deficiency of glucose-6-phosphate dehydrogenase
  • Refusal to participate in the study
  • Inability to follow the instructions

Study & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
One-day low fiber dietOne-day Low fiber dietPatients assigned to the active comparator will receive oral and written instructions about the same structured low fiber diet designed by an Endocrinologist but they will follow this diet only the day before colonoscopy. 2 liters of polyethylene glycol plus ascorbic acid will be administered
One-day low fiber dietPolyethylene Glycol plus ascorbic acidPatients assigned to the active comparator will receive oral and written instructions about the same structured low fiber diet designed by an Endocrinologist but they will follow this diet only the day before colonoscopy. 2 liters of polyethylene glycol plus ascorbic acid will be administered
Three-day low fiber dietThree-day low fiber dietPatients assigned to the experimental group will receive oral and written instructions about a structured low fiber diet designed by an Endocrinologist. They must follow this diet three days before colonoscopy. 2 liters of polyethylene glycol plus ascorbic acid will be administered
Three-day low fiber dietPolyethylene Glycol plus ascorbic acidPatients assigned to the experimental group will receive oral and written instructions about a structured low fiber diet designed by an Endocrinologist. They must follow this diet three days before colonoscopy. 2 liters of polyethylene glycol plus ascorbic acid will be administered
Primary Outcome Measures
NameTimeMethod
Boston Bowel Preparation Scale7 months

This scale goes from 0 (no preparation) to 3 points (excellent preparation) in the three segments of the colon (Proximal, transverse and distal). Maximum punctuation is 9 points

Secondary Outcome Measures
NameTimeMethod
Proportion of polyps detected in each arm7 months

Number of polyps detected in one arm/total of polyps detected

Degree of satisfaction with diet7 months

It will be assessed using a visual scale (1 excellent to 10 unbearable)

Trial Locations

Locations (1)

Department of Gastroenterology

🇪🇸

La Laguna, Santa Cruz De Tenerife, Spain

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