A Randomized Prospective Trial Comparing Pico-Salax (Magnesium Citrate) Plus Bisacodyl Versus Split Dose Polyethylene Glycol-Based Lavage In Preparation Of Patients For Colonoscopy
All patients referred to the Forzani MacPhail Colon Cancer Screening Centre (CCSC) in
Calgary, Alberta, Canada for colonoscopy will be considered for inclusion. During
pre-assessments at the clinic, patients are asked to consider a general research consent. If
they agree to that, then they will be approached for consideration of participating in this
study and presented with an "Invitation to Participate in a Research Study" form (appendix);
the study assistant will obtain final consent if they agree. Those not interested in
participating will simply receive their physician's standard bowel preparation protocol.
There will be no coercion of any sort. Enrollment of participants will be performed with
block randomizations of 8 by 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) oral Pico-Salax (two sachets, with 1.5-2L of water following each sachet)
with Dulcolax (Bisacodyl, 4 tablets); (2) split dose Polyethylene Glycol-Based Lavage (2L +
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, which has been modified from a previously used questionnaire, to be completed
once their bowel preparation is finished and before coming to the CCSC for the colonoscopy
(included in the appendix). Patient concerns or questions regarding the preparation will be
directed toward the study assistant or clinic nurses as opposed to their endoscopist, so as
to avoid un-blinding the Colonoscopist. The physician performing the procedure will then
complete an Ottawa Bowel Preparation Scale and a validated Simplified Bowel Preparation
scale to assess colon cleanliness.
Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind (Outcomes Assessor)
Quality of Bowel Cleanliness
Ottawa bowel Prep scale will be done by the Dr. to assess the quality of bowel cleanliness. The right, mid and rectosigmoid colon are each rated on a 5-point scale (0-4). Also, a complete 3-point rating for overall colonic fluid is assessed giving an overall score range of 0-14. An excellent preparation would score 0-1; a good preparation, 2-4; while scores >4 would indicate progressively worsening bowel preparations. A completely unprepared colon would score 11-14, depending on the amount of fluid. A simplified overall cleanliness score will be completed and compared to the Ottawa scale.
Scales provided to physician at time of colonoscopy, and filled out and collected after procedure is completed (1 hour time). Questionnaires are manually entered by an assistant into the study database on the same day as collection.
Alaa Rostom, MD
University of Calgary Faculty of Medicine
Canada: Ethics Review Committee