title: Monitoring colonoscopy withdrawal time significantly improves the adenoma detection rate and the performance of endoscopists.
abstract: OBJECTIVE
  The recommended minimum withdrawal time for screening colonoscopy is 6 minutes. Adenoma detection rates (ADRs) increase with longer withdrawal times. We aimed to compare withdrawal times and ADRs of endoscopists unaware of being monitored vs. aware.
  
  
  METHODS
  Seven experienced gastroenterologists prospectively performed 558 screening colonoscopies during a 9-month period in a Swiss University hospital. Colonoscopy withdrawal times were first measured without the gastroenterologists’ knowledge of being monitored (n = 355 colonoscopies) and then with their knowledge (n = 203 colonoscopies).
  
  
  RESULTS
  The median withdrawal time when gastroenterologists were unaware of being monitored was 4.5 minutes (interquartile range [IQR] 4 – 5.5 minutes) without intervention and 6 minutes (IQR 4 – 9 minutes) with intervention, increasing significantly to 7.3 minutes (IQR 6.5 – 9 minutes) and 8 minutes (IQR 7 – 11 minutes), respectively, when they were aware of being monitored (P < 0.001 both for colonoscopies with and without intervention). The ADR increased from 21.4 % when the gastroenterologists were unaware of being monitored to 36.0 % when they were aware (P < 0.001). In the multivariate regression model, the endoscopists knowing they were being monitored was the strongest factor associated with ADR (odds ratio 4.417; 95 % confidence interval [CI] 2.241 – 8.705; P < 0.001).
  
  
  CONCLUSIONS
  Colonoscopy withdrawal time in unmonitored gastroenterologists is shorter than recommended and increases with awareness of monitoring. ADR significantly increases when gastroenterologists are aware of being monitored. Implementation of systematic monitoring, and analysis of withdrawal time and ADR for each endoscopist may help to increase the ADR.
authors.affiliation: Division of Gastroenterology and Hepatology, Triemlispital, Zurich, Switzerland.
authors.forename: Stephan R
authors.initials: SR
authors.lastname: Vavricka
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Switzerland.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Sulz
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Basel, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Degen
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Switzerland.
authors.forename: Roman
authors.initials: R
authors.lastname: Rechner
authors.affiliation: Division of Gastroenterology and Hepatology, Claraspital, Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Manz
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Switzerland.
authors.forename: Luc
authors.initials: L
authors.lastname: Biedermann
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Basel, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Beglinger
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Basel, Switzerland.
authors.forename: Shajan
authors.initials: S
authors.lastname: Peter
authors.affiliation: Institute of Social and Preventive Medicine, University of Bern, Switzerland.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Safroneeva
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Rogler
authors.affiliation: Division of Gastroenterology and Hepatology, Centre Hospitaler Universitaire Vaudois/CHUV, Lausanne, Switzerland.
authors.forename: Alain M
authors.initials: AM
authors.lastname: Schoepfer
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D002983:Clinical Competence / Q000706:statistics & numerical data*; D003113:Colonoscopy / Q000379:methods* / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D055088:Early Detection of Cancer / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors