Anticipated Impacts on Veterans Health Care: 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. Background: 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. Objectives: 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). Methods: the study will be 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. This pragmatic trial will be conducted with a waiver of informed consent. Providers who are ordering a colonoscopy at the point of care will be asked to choose between allowing the patient to be enrolled in the study or continuing with the current standard 4L PEG within the context of the VA electronic medical records (EMR) ordering menu. Enrolled patients will be automatically randomized through the EMR at the point of care 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.
From the patients' perspective, the most formidable part of the colonoscopy experience is the process of bowel cleansing. A poorly tolerated bowel preparation regimen often leads to incompletion of scheduled colonoscopies which in turn undermines the effectiveness of colonoscopy, increases cost, and decreases patient satisfaction. The current standard bowel preparation in the VA is of larger volume and less palatable than another commonly used bowel preparation regimen. We propose to compare these two commonly used bowel preparations with respect to the overall completion rate of scheduled colonoscopies in a real-world VA practice setting. The results of the study can be immediately applied to maximize the effectiveness of colonoscopy and increase patient satisfaction in the VA.
