Retrospective Cohort Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Endosc. Nov 16, 2022; 14(11): 672-683
Published online Nov 16, 2022. doi: 10.4253/wjge.v14.i11.672
Quality of colonoscopy performed by medical or surgical specialists and trainees in five Australian hospitals
Tsai-Wing Ow, Olga A Sukocheva, Vy Tran, Richard Lin, Shawn Zhenhui Lee, Matthew Chu, Bianca Angelica, Christopher K Rayner, Edmund Tse, Guru Iyngkaran, Peter A Bampton
Tsai-Wing Ow, Olga A Sukocheva, Vy Tran, Richard Lin, Christopher K Rayner, Edmund Tse, Peter A Bampton, Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide 5000, SA, Australia
Tsai-Wing Ow, Department of Gastroenterology and Hepatology, Flinders Medical Centre, Bedford Park 5042, SA, Australia
Shawn Zhenhui Lee, Matthew Chu, Department of Gastroenterology and Hepatology, The Queen Elizabeth Hospital, Woodville South 5011, SA, Australia
Bianca Angelica, Department of Gastroenterology, Royal Darwin Hospital, Darwin 0810, NT, Australia
Guru Iyngkaran, Department of Gastroenterology and Hepatology, Royal Melbourne Hospital, Parkville 3050, VIC, Australia
Author contributions: Ow TW, Rayner CK, Tse E, Iyngkaran G and Bampton PA were involved in the conception of the study; Ow TW, Tran V, Lin R, Lee SZ, Chu M and Angelica B collected the data; Ow TW performed the analysis and drafted the manuscript; Sukocheva OA, Iyngkaran G and Bampton PA critically reviewed the manuscript and data analysis; the final manuscript was approved by all authors.
Institutional review board statement: The study was reviewed and approved by the Central Adelaide Local Health Network ethics committee (reference number: 13167).
Informed consent statement: A waiver of consent was granted for this retrospective study by the ethical review board as participant involvement in the study carried no more than low risk. Please refer to the institutional review board approval document.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: Original data collected in this study cannot be shared publicly because of ethics approval limitation. Data are available from the CALHN ethics committee (contact for researchers who meet the criteria for access to confidential data.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Tsai-Wing Ow, FRACP, MBBS, Doctor, Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Port Road, Adelaide 5000, SA, Australia.
Received: August 19, 2022
Peer-review started: August 19, 2022
First decision: September 2, 2022
Revised: September 19, 2022
Accepted: October 31, 2022
Article in press: October 31, 2022
Published online: November 16, 2022

Ensuring colonoscopy procedure quality is vital to the success of screening and surveillance programmes for bowel cancer in Australia. However, the data on the performance of quality metrics, through adequate adenoma detection, bowel preparation, and procedure completion rates, in the Australian public sector is limited. Understanding these can inform quality improvement to further strengthen our capacity for prevention and early detection of colorectal cancer.


To determine the quality of colonoscopy in Australian teaching hospitals and their association with proceduralist specialty, trainee involvement, and location.


We retrospectively evaluated 2443 consecutive colonoscopy procedure reports from 1 January to 1 April, 2018 from five public teaching tertiary hospitals in Australia (median 60 years old, 49% male). Data for bowel preparation quality, procedure completion rates, and detection rates of clinically significant adenomas, conventional adenomas, and serrated lesions was collected and compared to national criteria for quality in colonoscopy. Participating hospital, proceduralist specialty, and trainee involvement indicators were used for stratification. Data was analysed using Chi-squared tests of independence, Mann-Whitney U, One-way ANOVA, and multivariate binary logistic regression.


Fifty-two point two percent (n = 1276) and 43.3% (n = 1057) were performed by medical and surgical proceduralists respectively, whilst 29.8% (n = 728) involved a trainee. Inadequate bowel preparation affected 7.3% of all procedures. The procedure completion rate was 95.1%, which increased to 97.5% after adjustment for bowel preparation quality. The pooled cancer, adenoma, and serrated lesion detection rates for all five hospitals were 3.5%, 40%, and 5.9% respectively. Assessed hospitals varied significantly by patient age (P < 0.001), work-force composition (P < 0.001), adequacy of bowel preparation (P < 0.001), and adenoma detection rate (P < 0.001). Two hospitals (40%) did not meet all national criteria for quality, due to a procedure completion rate of 94.5% or serrated lesion detection rate of 2.6%. Although lower than the other hospitals, the difference was not significant. Compared with surgical specialists, procedures performed by medical specialists involved older patients [65 years (inter-quartile range, IQR 58-73) vs 64 years (IQR 56-71); P = 0.04] and were associated with a higher adenoma detection rate [odds ratio (OR) 1.53; confidence interval: 1.21-1.94; P < 0.001]. Procedures involving trainee proceduralists were not associated with differences in the detection of cancer, adenoma, or serrated lesions, compared with specialists, or according to their medical or surgical background. On multivariate analysis, cancer detection was positively associated with patient age (OR 1.04; P < 0.001) and negatively associated with medical compared to surgical proceduralists (OR 0.54; P = 0.04). Conventional adenoma detection rates were independently associated with increasing patient age (OR 1.04; P < 0.001), positively associated with medical compared to surgical proceduralists (OR 1.41; P = 0.002) and negatively associated with male gender (OR 0.53; P < 0.001).


Significant differences in the quality of colonoscopy in Australia exist, even when national benchmarks are achieved. The role of possible contributing factors, like procedural specialty and patient gender need further evaluation.

Keywords: Colonoscopy, Quality of health care, Adenoma detection rate, Bowel preparation quality, Hospital-based teaching

Core Tip: We evaluated the quality of colonoscopy performed at five teaching hospitals in Australia, using bowel preparation quality, procedure completion, and detection of cancer, adenoma, and serrated lesions as main indicators. In our retrospective analysis of 2443 procedures, the collective performance met national benchmarks for quality. However, two hospitals individually failed to meet all national benchmarks and we observed significant differences in key metrics of adenoma detection and adequacy of bowel preparation for colonoscopy across all hospitals. Higher adenoma detection rates were also independently shown amongst medical compared with surgical proceduralists, and amongst female patients.