Prospective analysis of factors associated with inadequate bowel preparation for colonoscopy in actual clinical practice

BACKGROUND/AIMS: Inadequate bowel preparation can result in prolonged procedure time and increased missed lesion and complication rates. This prospective study aimed to evaluate bowel preparation quality and identify the predictive factors for inadequate bowel preparation in actual clinical practice. METHODS: We included 399 patients who underwent colonoscopy between June 2015 and July 2016. Using the Aronchick bowel preparation scale, we defined a score ≤2 as adequate preparation and a score >2 as inadequate preparation. RESULTS: Mean patient age was 58.38±12.97 years; 60.6% were male. Indications for colonoscopy included screening (69.7%) and surveillance after polyp removal (21.3%). A split-dose regimen was prescribed to 55.4% of patients. The inadequate bowel preparation rate was 28.1%. Overall, the median time between the last bowel preparation agent dose and start of colonoscopy was 5.0 hours (range, 1.5–16.0 hours); that of the adequate group was 5.0 hours (range, 1.5–16.0 hours); and that of the inadequate group was 5 hours (range, 2–23 hours). The mean bowel preparation scale score of the ascending colon (1.94±0.25) was significantly higher than that of other colon segments. On multivariate analysis, elderly age, history of cerebrovascular disease, history of gastrectomy or appendectomy, and total preparation solution uptake <2 L were the independent predictors of inadequate bowel preparation. CONCLUSIONS: The inadequate bowel preparation rate was 28.1%. Risk factors included elderly age and history of cerebrovascular disease or abdominal surgery. Patients with these risk factors require special care and education.