title: Duration of the interval between the completion of bowel preparation and the start of colonoscopy predicts bowel-preparation quality.
abstract: BACKGROUND
  Recent studies suggest that colonoscopies done in the morning have better-quality bowel preparations than those done in the afternoon.
  
  
  OBJECTIVE
  We aimed to determine how the duration of the interval between the end of the preparation and the start of the colonoscopy affects preparation quality.
  
  
  METHODS
  We prospectively studied consecutive outpatients who had colonoscopies performed at our hospital within a 3-month period. The time of day when the colonoscopy started and the time interval from the last dose of preparation agent to the start of the colonoscopy were recorded. The endoscopist graded the quality of the preparation in the right side of the colon by using a 5-point visual scale.
  
  
  METHODS
  We studied 378 patients (96% men, mean age 62.2 years) who received preparations of polyethylene glycol electrolyte-based (PEG) and sodium phosphate (SP) solution (71%), oral PEG and magnesium citrate (23%), or SP alone (6%).
  
  
  RESULTS
  Compared with patients whose preparations were graded as 2/3/4 (fair/poor/inadequate), those whose preparations were graded as 0/1 (excellent/good) had a significantly shorter interval between the time of the last preparation agent dose and the start of the colonoscopy (P = .013).
  
  
  CONCLUSIONS
  We used a nonvalidated scale to assess the quality of bowel preparation.
  
  
  CONCLUSIONS
  Bowel-preparation quality varies inversely with the duration of the interval between the last dose of the bowel-preparation agent and the start of colonoscopy. This interval appears to be a better predictor of bowel-preparation quality than the time of day when colonoscopy is performed.
authors.affiliation: Department of Internal Medicine, Dallas Veteran's Affairs Medical Center, Dallas, Texas 75216, USA. asiddiqu2004@yahoo.com
authors.forename: Ali A
authors.initials: AA
authors.lastname: Siddiqui
authors.forename: Kenneth
authors.initials: K
authors.lastname: Yang
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Spechler
authors.forename: Byron
authors.initials: B
authors.lastname: Cryer
authors.forename: Raquel
authors.initials: R
authors.lastname: Davila
authors.forename: Daisha
authors.initials: D
authors.lastname: Cipher
authors.forename: William V
authors.initials: WV
authors.lastname: Harford
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002400:Cathartics; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D011446:Prospective Studies; D013997:Time Factors; D055815:Young Adult
chemical_list: D002400:Cathartics