Comparison of Low Volume PEG-Asc and Lower Volume PEG-Asc With Bisacodyl
Condition: Bowel Disease; Colon Adenoma
MeSH terms: Adenoma
Study type: Interventional
Phase: Phase 3

Summary: 
      Recently a low-volume polyethylene glycol containing ascorbic acid (PEG-Asc) formulation has
      proven as safe and effective as traditional 4-L PEG solutions for colonoscopy preparation.
      However, currently available aqueous purgative formulations are poorly tolerated. The aim of
      this study was to compare a split-dose 2-L PEG-Asc and a 1-L PEG-Asc with bisacodyl (10 mg)
      formulation to determine the quality of bowel cleansing and patient tolerability.
    

Detailed description: 
      - Study design A single center, randomized, comparative observer-blinded study was performed
      from May 2015 to September 2015 at the Department of Gastroenterology and Digestive Endoscopy
      at Korea University Anam Hospital (Seoul, Korea).

      In total, 200 outpatients received lower volume 1-L PEG with ascorbic acid plus bisacodyl
      (1L-PEG/AB) or low volume 2-L PEG with ascorbic acid (2L-PEG/A) in a 1:1 ratio.

      At the time of registration, subjects were randomly allocated to either group. They were
      randomized by a computer-generated list and were provided with written instructions. All
      patients provided written informed consent.

        -  Patients All patients between the ages of 20 and 75 years. Patients were excluded from
           the analysis if they had known or suspected gastrointestinal obstruction, Ileus, severe
           heart failure, uncontrolled hypertension (systolic pressure > 170 mmHg, diastolic
           pressure > 100 mmHg), severe constipation, clinically significant electrolyte
           abnormalities, any prior bowel resection, or significant gastroparesis.

        -  Bowel preparation In the 2L-PEG/A group, 1 L of PEG containing ascorbic acid was taken
           at 8:00 pm on the day before the colonoscopy, followed by an extra 500 mL of water. The
           second 1-L of PEG containing ascorbic acid was taken 4 h before the colonoscopy
           examination, with an additional 500 mL of water. Each liter of preparation and the extra
           500 mL water had to be consumed within 2 h of the procedure.

      The 1L-PEG/AB group received 10 mg bisacodyl at 9:00 pm on the day before the colonoscopy.
      Four hours before the colonoscopy examination, 1 L of PEG containing ascorbic acid was taken,
      followed by an additional 1 L of water. The preparation was completed 2 h before the
      examination. All colonoscopies were performed between 9 am and 1 pm.

      - Assessment by endoscopists Colonoscopies were performed by two expert endoscopists who were
      blinded to the preparation regimen. These two endoscopists worked for more than 5 years at
      our institution.

      Bowel cleansing was scored by the same endoscopist performing the colonoscopy. To assess the
      cleansing quality of the bowel preparations, the Boston Bowel Preparation Scale (BBPS) and
      the Aronchick Bowel Preparation Scale (ABPS) were used.

      - Assessment of patient tolerability and adverse events Before the colonoscopy procedure,
      patients completed questionnaires about their symptoms associated with the preparations to
      assess tolerability. Patients were asked to assess the degree of abdominal fullness,
      abdominal pain, nausea, vomiting, sleep disturbances, and general discomfort using a 5-point
      scale (i.e., none, mild, moderate, severe, or very severe).

      The palatability of the preparation was graded in 5 categories: very good, good, acceptable,
      disgusting, and bad.

      - Sample size and statistical analysis A sample size of at least 89 patients group was
      required for each treatment group to detect a difference in treatment success of a 5% type-I
      error rate and 80% power for a two-tailed χ2 test. Our sample size was based on the results
      from a pilot study that was conducted in our hospital and included 35 patients in each group.
      It was estimated that the efficacy for excellent treatment success would be 49% with PEG-2L/A
      and 30% with PEG-1L/AB. Based on these data, we decided to collect 100 patients per treatment
      group for study.

      Continuous variables were expressed as mean ± standard deviation (SD), and discontinuous
      variables were expressed as counts and percentages. SPSS 20.0 for Windows (SPSS Inc.,
      Chicago, IL, US) was used for data entry and statistical analyses. For the analyses between
      the two treatment groups, Students t-test as appropriate was used to compare continuous
      variables and either the Chi-square or Fisher's exact test were used for categorical data.
      The p-values < 0.05 were considered statistically significant.
    

Intervention name(s): Polyethylene Glycols; Bisacodyl
Intervention type(s): Drug; Drug
Intervention description(s): (Split dose 2L PEG-Asc); (1L PEG-Asc plus bisacodyl)
Other intervention name(s): Coolprep®; Taejoon Pharmaceuticals, Seoul, Korea; Coolprep®; Taejoon Pharmaceuticals, Seoul, Korea; Dulcorax-S®; Boehringer Ingelheim, Seoul, Korea
Intervention MeSH terms: Bisacodyl
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Keywords: Bowel preparation; Ascorbic acid; Bisacodyl; Polyethylene glycol