Modelling characteristics of inadequate bowel preparations for colonoscopy

Abstract

Background and Aims Colonoscopy remains the gold standard for colon cancer screening, but poor bowel preparation (BP) results in an inadequate examination. We sought to determine factors associated with poor BP. Methods In this prospective quality improvement study, data were serially gathered from 649 patients prior to colonoscopy at an academic medical centre with using a survey. Recipients with adequate BP were compared to those with inadequate BP. Results Bowel preparation was inadequate in 20.9% (N = 136) of colonoscopies. Risk factors for inadequate BP included male gender (OR 2.1, 95% CI 1.3‐3.4, P = 0.0039), chronic obstructive pulmonary disease (COPD) (OR 3.9, 95% CI 1.9‐7.9, P = 0.0002), diabetes mellitus with end‐organ damage (OR 11.7, 95% CI 5.6‐24.6, P < 0.0001), severe neurologic disease (OR 5.1, 95% CI 2.2‐11.8, P < 0.0002), medications to treat constipation (OR 2.0, 95% CI 1.2‐3.5, P = 0.0129), tricyclic antidepressant use (OR 7.5, 95% CI 3.1‐18.4, P < 0.0001), non‐utilization of a split prep (OR 5.3, 95% CI 3.1‐9.0, P < 0.0001), incomplete BP (OR 3.5, 95% CI 2.0‐6.3, P < 0.0001) and non‐adherence to clear liquid diet instructions (OR 4.3, 95% CI 2.2‐8.6, P < 0.0001). Modelling inadequate preparation with these variables demonstrated an area under the receiver operating curve of 0.8525 indicating utility in predicting inadequate BP. Conclusions The likelihood of inadequate BP is strongly influenced by advanced medical comorbidities, medications and type of BP. This information can help determine which patients are at higher risk for inadequate BP and may allow providers to adjust the prescribed BP leading to improved colonoscopy visualization, reduced procedure time and reduced healthcare costs.