Single Dose Versus Split Dose Polyethylene Glycol-based Colonic Lavage for Colonoscopy
Condition: Colonoscopy Preparation
Study type: Interventional

Summary: 
      Proper bowel cleansing prior is an essential requirement for the conduct of colonoscopy.
      However, due to the nature of cleansing process, the ideal bowel cleansing preparation
      remains elusive.

      The objective of this study is to compare the efficacy, safety and tolerability of oral
      polyethylene glycol lavage given either as a single dose or split dose. The study will be a
      randomized controlled single blind two group study. The primary study outcomes will be the
      previously validated Ottawa bowel preparation score.
    

Detailed description: 
      All patients between the age of 50 and 75 years referred to the Forzani & MacPhail Colorectal
      Cancer Screening Centre in Calgary, Alberta, Canada for colonoscopy will be considered for
      inclusion. During pre-assessments at the clinic, patients will be asked to participate in the
      study by a nurse clinician. If they agree - final consent will be obtained by a
      gastroenterologist along with consent for the colonoscopy. Those not interested in
      participating will simply receive their physicians standard bowel preparation protocol. There
      will be no coercion of any sort.

      Patients with acute coronary syndrome, congestive heart failure, unstable angina, known or
      suspected renal failure, ascites, megacolon, known or suspected bowel obstruction, or other
      comorbidities that may prevent colonoscopy will be excluded. Patients will also be excluded
      if they previously had partial or subtotal colectomy or if the colonoscopy is warranted for
      the evaluation of diarrhea.

      Enrollment of participants will be performed with block randomizations of 8 stratified by AM
      versus PM procedure time using a computer-generated table, with allocation concealment
      maintained through the use of consecutively numbered sealed envelopes. Colonoscopists and
      investigators will be blinded to allocation groups. Patients will be allocated to one of two
      groups: (1) 4L PEG day prior to procedure; (2) 4L of PEG split in two 2L doses

      A study assistant will assign patients to their group and instruct them on the proper use of
      their assigned bowel preparation method. Patients will be given a tolerability questionnaire,
      that was modified from a previously reported questionnaire, to be completed once their bowel
      preparation is finished and before coming to the hospital for the colonoscopy. Patient
      concerns or questions regarding the preparation will be directed toward the assistant as
      opposed to their gastroenterologist, so as to avoid unblinding the gastroenterologist.

      Outcomes

      The previously validated Ottawa bowel preparation scale80 will be used to assess the quality
      of bowel cleanliness. Each of the right, mid and rectosigmoid colon is rated on a 5-point
      scale (0-4). In addition, a complete 3-point rating for overall colonic fluid is assessed
      resulting in an overall score range of 0 to 14. An excellent preparation with little fluid
      would score 0 to 1; a good preparation, 2 to 4; while scores higher than 4 would indicate
      progressively worsening bowel preparations. A completely unprepared colon would score 11 to
      14, depending on the amount of colonic fluid.

      Colonoscopy will be performed in a standard fashion and endoscopists will rate the
      bowel-preparation quality during the procedure and record the result on a separate
      standardized form.

      Secondary outcomes will include a previously validated tolerability questionnaire and patient
      and investigator reported adverse events.
    

Intervention name(s): Polyethylene Glycol; polyethylene glycol
Intervention type(s): Drug; Drug
Intervention description(s): 4 Litres of polyethylene glycol bowel preparation solution; Polyethylene glycol 4L given in two split doses of 2L each
Other intervention name(s): co-lyte; Go-lyte; PEG; PEG; Co-lyte; Go-lyte
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Care Provider, Investigator, Outcomes Assessor)
Keywords: bowel preparation; bowel purgative; bowel cleansing; colonoscopy