S425 Preparing for Success: Enhanced Bowel Preparation Protocol Significantly Reduces Inadequate Colonoscopy Preparation, a Retrospective Study of 1,850 Patients

Introduction: Inadequate bowel preparation leads to cancellation or incomplete visualization in 6%–30% of colonoscopies, highlighting the need for improved bowel preparation protocols. Methods: At our institution, the standard bowel preparation consisted of a 3-day low-fiber diet, 1 day of clear liquids, and a split-dose regimen of 64 oz polyethylene glycol (PEG). A modified protocol was introduced, extending the duration of low-fiber diet to 7 days and adding 20 mg of bisacodyl and 500 mg of simethicone the evening before the procedure. We conducted a retrospective analysis of 1,850 patients undergoing colonoscopy (925 patients in each arm). Variables assessed included demographic characteristics (age, gender, body mass index), comorbidities (e.g., diabetes, cirrhosis, stroke, dementia, inflammatory bowel disease, constipation), prior abdominal surgery, American Society of Anesthesiologists (ASA) class, functional status, incarceration status, substance use (alcohol, tobacco, marijuana), and medication use (narcotics, benzodiazepines, methadone, tricyclic antidepressants [TCAs], other antidepressants, anticholinergics, antipsychotics, laxatives). Results: Factors independently associated with poor bowel preparation included anticholinergic use (odds ratio [OR] 1.4, P = 0.007), baseline laxative use (OR 1.77, P = 0.008), higher ASA class (OR 1.77, P < 0.001), and marijuana use (OR 1.9, P = 0.018). TCA use demonstrated a trend toward significance (OR 1.8, P = 0.072). Following implementation of the updated protocol, “excellent” preparation rates improved from 35.51% to 42.49%, and “poor” preparation rates decreased from 3.78% to 1.62% (χ² = 11.65, P = 0.009). The combined “inadequate or poor” preparation rate declined from 10.7% to 7.78% (χ² = 4.69, P = 0.03). On multivariate analysis, the updated protocol was associated with reduced odds of inadequate or poor preparation (OR 0.66, 95% CI: 0.47–0.93, P = 0.017). Conclusion: A 7-day low-fiber diet combined with bisacodyl and simethicone significantly improves bowel preparation quality compared to the standard regimen. These modifications reduced inadequate preparation rates and have the potential to enhance colonoscopy outcomes.