No Stool Out, Then Itʼs Still In: Inability to Evacuate Stool Immediately Prior to Colonoscopy Is a Predictor for Inadequate Bowel Preparation: 500

Introduction: Poor bowel preparation increases intubation time, decreases polyp detection, and necessitates repeat colonoscopies. No effective method to detect poor preparation prior to colonoscope insertion has been described. As such, we have attempted to analyze stool volatile organic compounds to determine the adequacy of bowel preparation prior to colonoscope insertion. During collection we noted a number of patients unable to provide stool samples prior to colonoscopy. Here we present the risk of poor preparation in those unable to provide stool samples versus those able to provide stool samples prior to colonoscopy. Methods: Patients were asked to provide stool samples before colonoscopy evaluation. We noted patients who were able to provide a sample and patients who were unable to provide a sample. Following colonoscopy, the charts were reviewed to note the quality of bowel preparation recorded by the performing endoscopist. Preparation was recorded as Excellent, Good, Fair, or Poor. Endoscopists also recorded bowel preparation as adequate (defined as ability to detect all polyps ≥ 5 mm) or inadequate. Statistical analysis of the risk for poor or inadequate bowel preparation in patients unable to give a stool sample versus those able to provide a stool sample was performed. Results: 80 patients were approached to provide stool samples prior to colonoscopy. 64 patients were able to provide samples, of which 2 had poor or inadequate bowel preparations (3%). 16 patients were unable to provide samples, of which 6 had poor or inadequate bowel preparations (37.5%). Relative risk for poor or inadequate bowel preparation in patients unable to provide stool samples was 12 (CI 2.7 to 54, p-value 0.0006). Further assessment showed that patients unable to provide a stool sample prior to colonoscopy had a relative risk of 6.3 (CI 2.9 to 14; p-value < 0.001) for combined outcome of fair/poor/inadequate bowel preparation. Conclusion: Inability to provide a stool sample before colonoscopy is a significant risk factor for suboptimal bowel preparation. These results suggest that patients should be asked to provide stool samples prior to sedation and colonoscope insertion. Further bowel preparation could then be considered for those unable to provide a stool sample. This may reduce poor bowel preparations, improving endoscopy suite efficiency, the quality of colonoscope evaluation, and reducing the need for repeat procedures.