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IIR 15-346 – HSR Study

IIR 15-346
Comparative Effectiveness of Split-Dose Colonoscopy Bowel Preparation Regimens
Yu-Xiao Yang, MD MSCE
Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
Philadelphia, PA
Funding Period: October 2017 - September 2024
Colorectal cancer (CRC) is a leading cause of cancer-related death among Veterans. Colonoscopy can effectively reduce CRC incidence and mortality. However, non-adherence to screening colonoscopy substantially undermines this benefit. Existing evidence indicates that a disagreeable bowel preparation is a leading barrier to completing a colonoscopy from the patients' perspective. The taste and the volume of the bowel preparation determine patient tolerability and compliance to the preparation instructions, which in turn affects the incompletion (e.g., cancellation/no-show/reschedule) rate of scheduled colonoscopies as well as the effectiveness of the completed colonoscopies and patient satisfaction. The two most commonly used preparations currently in the US are the split-dose 4L polyethylene glycol (PEG) and the split-dose 2L MiraLAX/Gatorade preparations. While a high-volume regimen may in theory be more effective than a lower volume one, it may be associated with lower tolerability and adherence in real-world practice. Three small trials have compared these two preparations. However, data from these explanatory trials cannot inform policy decisions because they were conducted under artificial conditions, restricted among narrow patient populations, and most importantly not designed to capture the full impact of bowel preparation on the completion rate or effectiveness of colonoscopy. To address this critical knowledge gap, we are proposing a pragmatic trial to determine the optimal split-dose bowel preparation in the general veteran population.

To compare the real-world effectiveness of the two most commonly used split-dose colonoscopy bowel preparation regimens in the US (i.e., 4L PEG and 2L MiraLAX/Gatorade) with respect to the completion rate of scheduled colonoscopies, adenoma detection rate and secondarily preparation quality, cancellation/no-show rate and patient-oriented outcomes (e.g., willingness to repeat the preparation).

The study is a pragmatic randomized controlled trial comparing the two existing bowel preparation regimens in a large regional VA healthcare system. All Veterans who are > 18 years of age and undergoing an outpatient elective colonoscopy are eligible. Providers who are ordering a colonoscopy at the point of care will be asked to choose between allowing the patient to be contacted by study team via telephone for consideration of participating in the study or continuing with the current standard 4L PEG within the context of the VA electronic medical records (EMR) ordering menu. If both the provider and the patient agree that the patient may be contacted, the study team will contact the patient and obtain verbal informed consent. Patients who are eligible and consent to the study will be automatically randomized through the EMR to one of the two bowel preparation regimens, and a pre-populated order for the assigned preparation will then be presented instantaneously to the provider in the EMR for signature. Outcomes and covariates data will be collected directly from the EMR. The primary endpoints are overall completion rate of scheduled colonoscopy and adenoma detection rate, and the secondary endpoints are cancellation/no-show rate, bowel preparation quality and patient-oriented outcomes. Analysis will be based on intention-to-treat. We will also prospectively collect cost data in order to perform an economic evaluation of the two bowel preparation options.

-We developed a pictorial bowel prep instruction intended for patients.
-We have been able to successfully operationalized an electronic procedure using existing features of CPRS to allow patient tracking, enrollment, randomization, bowel prep ordering.

-The electronic automated procedure we developed for patient enrollment, patient tracking, research documentation, randomization can be adapted for future point-of-care pragmatic trials in the VA.
-By identifying a colonoscopy bowel preparation regimen which is the most effective in real-world VA practice and can be immediately implemented on a VA-wide scale, the proposed study will maximize the effectiveness of colonoscopy in reducing colorectal cancer (CRC) risk among veterans, increase veteran satisfaction, and reduce VA healthcare cost.

External Links for this Project

NIH Reporter

Grant Number: I01HX002133-01A2

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Journal Articles

  1. Patel D, Yang YX, Trivedi C, Kavani H, Xie D, Medvedeva E, Lewis J, Khan N. Incidence, Duration, and Management of Anemia: A Nationwide Comparison Between IBD and Non-IBD Populations. Inflammatory Bowel Diseases. 2020 May 12; 26(6):934-940. [view]

DRA: Health Systems, Cancer
DRE: Treatment - Comparative Effectiveness, TRL - Applied/Translational, Treatment - Efficacy/Effectiveness Clinical Trial
Keywords: Best Practices, Cancer, Effectiveness, Patient Preferences
MeSH Terms: none

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