title: Constipation, fiber intake and non-compliance contribute to inadequate colonoscopy bowel preparation: a prospective cohort study.
abstract: OBJECTIVE
  Adequate bowel preparation is important for colonoscopy. Currently available evidence on the determinants of poor bowel preparation is largely derived from studies in Western countries. We aimed to identify the risk factors for inadequate bowel preparation for colonoscopy in the Chinese population.
  
  
  METHODS
  In this single-center study, patients admitted to the Outpatient Department between March 2013 and December 2015 and had indications for colonoscopy were prospectively enrolled. Questionnaires were administered to the patients. Their characteristics and procedure-related parameters such as procedure time were recorded. Bowel preparation was assessed using Boston bowel preparation scale score.
  
  
  RESULTS
  A total of 409 patients with a mean age of 48.8 ± 12.9 years were enrolled in the study, 60.9% of whom were men. On univariate analysis, poor educational level (P = 0.020), chronic constipation (P = 0.001), taking no physical exercise after medication (P < 0.001), a high-fiber diet during the 24-h period immediately preceding the colonoscopy (P < 0.001), incomplete intake of medication (P < 0.001), the passage of yellow or dark stools before colonoscopy (P < 0.001), waiting time (P = 0.001) and stool frequency after medication (P = 0.048) were significantly associated with inadequate bowel preparation. On multivariate analysis, chronic constipation [odds ratio (OR) 2.05, 95% confidence interval (CI) 1.31-3.23, P = 0.002], incomplete intake of the medication (OR 2.77, 95% CI 1.47-5.21, P = 0.002) and a high-fiber diet within 24 h before colonoscopy (OR 2.15, 95% CI 1.40-3.28, P < 0.001) were independent risk factors for inadequate bowel preparation.
  
  
  CONCLUSIONS
  Chronic constipation, poor compliance with treatment and high-fiber diet were predictors of poor bowel preparation. Patients with these risk factors require more effective strategies for bowel preparation.
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Fang
authors.affiliation: Digestive Endoscopy Center, Changhai Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Hong Yu
authors.initials: HY
authors.lastname: Fu
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Ma
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Ya Ping
authors.initials: YP
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Yun Feng
authors.initials: YF
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Chun Ping
authors.initials: CP
authors.lastname: Zhu
authors.affiliation: Department of Gastroenterology, Shanghai, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qian
authors.affiliation: Department of Gastroenterology, Shanghai, China. baiyu1998@hotmail.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Gastroenterology, Shanghai, China. li.zhaoshen@hotmail.com.
authors.forename: Zhao Shen
authors.initials: ZS
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002400:Cathartics / Q000008:administration & dosage*; D002681:China; D002908:Chronic Disease; D003113:Colonoscopy / Q000379:methods / Q000523:psychology / Q000592:standards*; D003248:Constipation / Q000150:complications*; D004043:Dietary Fiber / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011092:Polyethylene Glycols / Q000008:administration & dosage; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D002400:Cathartics; D004043:Dietary Fiber; D011092:Polyethylene Glycols
keywords: bowel preparation; colonoscopy; constipation; efficacy; risk factors