title: Prospective multicenter randomized controlled trial comparing adenoma detection rate in colonoscopy using water exchange, water immersion, and air insufflation.
abstract: OBJECTIVE
  Adenoma detection rate (ADR), defined as the proportion of patients with at least one adenoma of any size, is a quality indicator. We tested the hypothesis that water exchange (WE) improves ADR but water immersion (WI) has no adverse effect on ADR compared with air insufflation (AI).
  
  
  METHODS
  A prospective study was conducted at the Dalin Tzu Chi Hospital in southern Taiwan and the Hualien Tzu Chi Hospital in eastern Taiwan on patients randomly assigned to WE, WI, or AI with stratification by the 3 study colonoscopists. The primary outcome was ADR.
  
  
  RESULTS
  From July 2013 to December 2015, 651 patients were recruited and randomized into 3 groups with a 1:1:1 ratio (217 patients per group). Overall, ADR met quality standards: WE 49.8% (95% CI, 43.2%-56.4%), AI 37.8% (95% CI, 31.6%-44.4%), and WI 40.6% (95% CI, 34.2%-47.2%). Compared with AI, WE significantly increased ADR (P = .016). There was no difference between WI and WE. ADRs of WI and AI were comparable. Compared with AI, WE confirmed a longer insertion time, higher cleanliness score, but similar adenoma per positive colonoscopy (APPC) and withdrawal time with polypectomy. Subgroup analysis found WE significantly increased ADR in propofol-sedated patients. Multivariate generalized linear mixed model analysis revealed that age ≥50 years, WE (vs AI), colonoscopy indication, no previous history of colonoscopy, and withdrawal time >8 minutes were significant predictors of increased ADR.
  
  
  CONCLUSIONS
  Confirmation of prior reports showing WE, but not WI, increased ADR further strengthened the validity of our observations. WE significantly increased ADR in propofol-sedated patients. The outcome differences justify assessment of the role of WE in colorectal cancer prevention. Similar APPC and withdrawal times suggest that adequate inspection was performed on colonoscope withdrawal in each of the study arms. (Clinical trial registration number: NCT01894191.).
authors.affiliation: Division of Gastroenterology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan; School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan.
authors.forename: Yu-Hsi
authors.initials: YH
authors.lastname: Hsieh
authors.affiliation: Division of Gastroenterology, Department of Medicine, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan; School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Tseng
authors.affiliation: School of Medicine, Buddhist Tzu Chi University, Hualien, Taiwan; Department of Gastroenterology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.
authors.forename: Chi-Tan
authors.initials: CT
authors.lastname: Hu
authors.affiliation: Department of Medical Research, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan; Dalla Lana School of Public Health, University of Toronto, Ontario, Canada.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Koo
authors.affiliation: Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hill, California, USA; David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
authors.forename: Felix W
authors.initials: FW
authors.lastname: Leung
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery; D000367:Age Factors; D000368:Aged; D000388:Air; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D054810:Deep Sedation; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives; D007101:Immersion; D007327:Insufflation; D008297:Male; D008875:Middle Aged; D015742:Propofol; D011446:Prospective Studies; D014867:Water
chemical_list: D006993:Hypnotics and Sedatives; D014867:Water; D015742:Propofol