Predicting inadequate bowel preparation for colonoscopy in participants receiving split-dose bowel preparation: development and validation of a prediction score

Gastrointest Endosc. 2015 Mar;81(3):665-72. doi: 10.1016/j.gie.2014.09.066. Epub 2015 Jan 17.


Background: Adequate bowel preparation is important for optimal colonoscopy. It is important to identify patients at risk for inadequate bowel preparation because this allows taking precautions in this specific group.

Objective: To develop a prediction score to identify patients at risk for inadequate bowel preparation who may benefit from an intensified bowel cleansing regimen.

Design: Patient and colonoscopy data were prospectively collected, whereas clinical data were retrospectively collected for a total of 1996 colonoscopies in participants who received split-dose bowel preparation. Multivariate logistic regression analyses were conducted in a random two-thirds of the cohort to develop a prediction model. Validation and evaluation of the discriminative power of the prediction model were performed within the remaining one-third of the cohort.

Setting: Four centers, including one academic and three medium-to-large size nonacademic centers.

Patients: Consecutive colonoscopies in November and December 2012. Mean age was 57.3 ± 15.9 years, 45.8% were male and indications for colonoscopy were screening and/or surveillance (27%), abdominal symptoms and/or blood loss and/or anemia (60%), inflammatory bowel disease (9%), and others (4%).

Interventions: Colonoscopy.

Main outcome measurements: Inadequate bowel preparation defined as Boston Bowel Preparation Scale score <6.

Results: A total of 1331 colonoscopies were included in the development cohort, of which 172 (12.9%) had an inadequate bowel preparation. Independent factors included in the prediction model were American Society of Anesthesiologists Physical Status Classification System score ≥3, use of tricyclic antidepressants, use of opioids, diabetes, chronic constipation, history of abdominal and/or pelvic surgery, history of inadequate bowel preparation, and current hospitalization. The discriminative ability of the scale was good, with an area under the curve of 0.77 in the validation cohort.

Limitations: Study design partially retrospective, no data on patient compliance.

Conclusion: We developed a validated, easy-to-use prediction scale that can be used to identify subjects with an increased risk of inadequate bowel preparation with good accuracy.

Publication types

  • Multicenter Study
  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cathartics / administration & dosage*
  • Citrates / administration & dosage*
  • Citric Acid / administration & dosage*
  • Colonoscopy*
  • Decision Support Techniques*
  • Female
  • Humans
  • Logistic Models
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Organometallic Compounds / administration & dosage*
  • Picolines / administration & dosage*
  • Polyethylene Glycols / administration & dosage*
  • Prospective Studies
  • Retrospective Studies
  • Risk Assessment
  • Sensitivity and Specificity


  • Cathartics
  • Citrates
  • Organometallic Compounds
  • Picolines
  • Citric Acid
  • Polyethylene Glycols
  • picosulfate sodium
  • magnesium citrate