Gut 62:236-241 doi:10.1136/gutjnl-2011-300167
  • Endoscopy
  • Original article

Factors determining the quality of screening colonoscopy: a prospective study on adenoma detection rates, from 12 134 examinations (Berlin colonoscopy project 3, BECOP-3)

  1. Thomas Rosch10
  1. 1Central Interdisciplinary Endoscopy, Charité Medical University, Campus Virchow Hospital, Berlin, Germany
  2. 2Department of Medical Biometry and Epidemiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
  3. 3Division of Gastroenterology, Portland VA Medical Centre, Portland, Oregon, USA
  4. 4Private Practice in Gastroenterology, Berlin, Germany
  5. 5Department of Interdisciplinary Endoscopy, University Hospital Hamburg-Eppendorf, Berlin Study Group Office, Berlin, Germany
  6. 6Charité Medical University, Campus Mitte Hospital, Institute for Social Medicine, Epidemiology and Health economy, Berlin, Germany
  7. 7Berlin Statistical Office, Berlin, Germany
  8. 8Charite, Universitatsmedizin Berlin, Campus virchow-klinikum, MED KLINIK M.S. Hepatologie U. Gastroenterologie, Berlin, Germany
  9. 9Central Research Institute of Ambulatory Health Care, Berlin, Germany
  10. 10Department of Interdisciplinary Endoscopy, University Hospital Hamburg-Eppendorf, Hamburg, Germany
  1. Correspondence to Professor Thomas Rosch, Department of Interdisciplinary Endoscopy, University Hospital Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany; t.roesch{at}
  1. Contributors AA was involved in the study organisation, monitoring and data collection; KW was responsible for the advanced statistical analysis, including data recalculation; DL was involved in study counselling and the writing of the manuscript; AA, JA, RD, MM, MM, MS, and AS performed the study colonoscopies and helped in the study organisation; KG was involved as a research fellow in data collection and monitoring; GS was the main research nurse; SR and UG were responsible for the data preparation and descriptive study statistics; BW did some initial study counselling; LA provided the data from the central screening colonoscopy registry; and TR was the PI of the study and was responsible for the study idea, study concept and planning, ethical committee application, data monitoring supervision and the writing of the manuscript.

  • Revised 10 February 2012
  • Accepted 11 February 2012
  • Published Online First 22 March 2012


Background Screening colonoscopy (SC) outcome quality is best determined by the adenoma detection rate (ADR). The substantial variability in the ADRs between endoscopists may reflect different skills, experience and/or equipment.

Objective To analyse the potential factors that may influence ADR variance, including case volume.

Design 12 134 consecutive SCs (mean age 64.5 years, 47% men) from 21 Berlin private-practice colonoscopists were prospectively studied during 18 months. The data were analysed using a two-level mixed linear model to adequately address the characteristics of patients and colonoscopists. The ADR was regressed after considering the following factors: sex, age, bowel cleanliness, NSAID intake, annual SC case volume, lifetime experience, instrument withdrawal times, instrument generations used, and the number of annual continuing medical education (CME) meetings attended by the physician. The case volume was also retrospectively analysed from the 2007 national SC registry data (312 903 colonoscopies and 1004 colonoscopists).

Results The patient factors that correlated with the ADR were sex, age (p<0.001) and low quality of bowel preparation (p=0.005). The factors that were related to the colonoscopists were the number of CME meetings attended (p=0.012) and instrument generation (p=0.001); these factors accounted for approximately 40% of the interphysician variability. Within a narrow range (6–11 min), the withdrawal time was not correlated with the ADR. Annual screening case volume did not correlate with the ADR, and this finding was confirmed by the German registry data.

Conclusions The outcome quality of screening colonoscopies is mainly influenced by individual colonoscopist factors (ie, CME activities) and instrument quality.

Clinical trial registration number Clinical Trial Gov Registration number: NCT00860665.


  • * RD Deceased October 2011.

  • Funding The Berlin Colonoscopy Screening Study was supported by a grant from Deutsche Krebshilfe e.V. (no. 108166) and by unrestricted grants from Olympus, Pentax and Falk Companies. There was no influence on study design, performance, data analysis or the writing of the manuscript.

  • Competing interests None.

  • Ethics approval Charité Ethical Committee (nr. EA 02/019/07).

  • Provenance and peer review Not commissioned; externally peer reviewed.