A Low Residue Diet with a Split Dose Bowel Prep Is Effective in Improving Bowel Prep Adequacy in a Veteranʼs Affairs Endoscopy Unit

Abstract

Introduction: To achieve an effective colon cancer screening program, it has been proposed that GI labs should have an adequate bowel prep for >85% of exams. The aim of this study is to compare the efficacy of standard prep involving 2 days of clear liquid diet (CLD) followed by polyethylene glycol (PEG) prep on the night prior to procedure with a modified prep involving a low residue diet (LRD) for 5 days leading up to the procedure followed by 1 day of CLD and a split prep with PEG. Secondary aim is to assess the impact on adequacy of bowel prep. Methods: This study has pre-post study design evaluating all colonoscopies before and after an institutional policy change in the method of bowel preparation. All patients who received outpatient colonoscopies at the Atlanta VA Medical Center during May, 2016 and May to June, 2017 were included in this study. Patients who received alternative prep instructions were excluded from this study. Procedures aborted for reasons unrelated to prep were excluded. Pre-procedure nurses queried patients about adherence to split prep instructions and adherence to LRD. The data was analyzed by a statistician using frequency tables that were produced to examine the overall distributions of gender, race, type of prep, and prep quality among the study population. Chi square tests of association were applied to cross-tabulated data to detect associations between overall prep quality and a set of relevant variables including type of prep and completion prep and consumption of LRD. Estimated odds ratios with corresponding 95% confidence intervals were considered to indicate strong association. Results: A total 506 patients met inclusion criteria. The bowel prep was adequate significantly more often in modified prep patients compared to standard prep patients (87% vs 79.7%, p=0.017). Among modified prep patients, the LRD produced an adequate prep more often than without the diet (90.1% vs 77%, p=0.005). Adequacy rates were highest in those who followed the LRD, irrespective of completing split prep instructions or not (90.2% vs 88.9%). Conclusion: Our study confirms that adherence to a split prep results in higher rates of adequate bowel prep. However, adding a LRD for 5 days leading up to the colonoscopy improves the adequacy of the bowel prep beyond split prep alone. These novel findings support adding LRD to increase bowel prep adequacy rates.1066_A Figure 1. Bowel Prep Quality based on type of prep1066_B Figure 2. Modified Bowel Prep Quality based low residue diet1066_C Figure 3. Modified Bowel Prep Quality based on type of prep and diet