PEG 4L with Bisacodyl 20 mg is Superior to PEG 4L Alone for Colonoscopy Preparation

Abstract

Purpose: Combination bisacodyl plus polyethylene glycol (PEG) is being used less frequently due to available alternatives and the concern for ischemic colitis. The purposes of our study were to identify whether the addition of bisacodyl 20mg to 4L PEG results in a better preparation than 4L PEG alone as a single dose preparation for colonoscopy and to review its safety in a large group of patients. Methods: We identified all outpatient colonoscopy exams performed between January 1, 2010 and July 1, 2011. We excluded cases in which the preparation was not 4L PEG alone or 4L PEG + 20mg bisacodyl. We recorded patient characteristics, preparation quality on a 5-point scale, procedure duration, and adenoma detection rate. Results: After screening 1,644 exams, 938 patients were identified (4L PEG n=574, 4L PEG + 20mg bisacodyl n=364). There was a marked difference in the proportion of individuals who had a good or excellent preparation in the 4L PEG + 20 mg bisacodyl group compared to the group receiving 4L PEG alone (88.5 vs. 77.4%). In a multivariate analysis, lower BMI (≤30) and use of 4L PEG + 20mg bisacodyl (OR=2.49;1.64-3.79) were independently associated with a good or excellent preparation. No cases of ischemic colitis were identified due to bisacodyl. Adenoma detection rate did not differ between preps (33.7 vs. 31.4% for PEG alone; P=0.47) Conclusion: Use of 4L PEG + 20mg bisacodyl results in a better preparation for colonoscopy than 4L PEG alone when using a day before single preparation approach. This did not affect the adenoma detection rate however. Although we saw no cases of ischemic colitis, we suggest using a 5mg dose of bisacodyl with 4L PEG which is consistent with FDA recommendations.