CC BY-NC-ND 4.0 · Endoscopy 2024; 56(04): 302-310
DOI: 10.1055/a-2214-9840
Original article

Initiatives to increase colonoscopy capacity – is there an impact on polyp detection? A UK National Endoscopy Database analysis

Liya Lu*
1   Population Health Sciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
Jamie Catlow
1   Population Health Sciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
2   Gastroenterology, University Hospital of North Tees, Stockton-on-Tees, United Kingdom
3   Gastroenterology, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, United Kingdom
Matthew D. Rutter
1   Population Health Sciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
2   Gastroenterology, University Hospital of North Tees, Stockton-on-Tees, United Kingdom
Linda Sharp
1   Population Health Sciences Institute, Newcastle University, Newcastle-upon-Tyne, United Kingdom
on behalf of the NED-APRIQOT study team › Author Affiliations
Supported by: Health Foundation AIMS ID 695428


Background To address mismatch between routine endoscopy capacity and demand, centers often implement initiatives to increase capacity, such as weekend working or using locums/agency staff (insourcing). However, there are concerns that such initiatives may negatively impact quality. We investigated polyp detection for weekend vs. weekday and insourced vs. standard procedures using data from the UK National Endoscopy Database.

Methods We conducted a national, retrospective, cross-sectional study of diagnostic colonoscopies performed during 01/01–04/04/2019. The primary outcome was mean number of polyps (MNP) and the secondary outcome was polyp detection rate (PDR). Multi-level mixed-effect regression, fitting endoscopist as a random effect, was used to examine associations between procedure day (weekend/weekday) and type (insourced/standard) and these outcomes, adjusting for patient age, sex, and indication.

Results 92 879 colonoscopies (weekends: 19 977 [21.5 %]; insourced: 9909 [10.7 %]) were performed by 2496 endoscopists. For weekend colonoscopies, patients were less often male or undergoing screening-related procedures; for insourced colonoscopies, patients were younger and less often undergoing screening-related procedures (all P < 0.05). Fully adjusted MNP was significantly lower for weekend vs. weekday (incidence rate ratio [IRR] 0.86 [95 %CI 0.83–0.89]) and for insourced vs. standard procedures (IRR 0.91 [95 %CI 0.87–0.95]). MNP was highest for weekday standard procedures and lowest for weekend insourced procedures; there was no interaction between procedure day and type. Similar associations were found for PDR.

Conclusions Strategies to increase colonoscopy capacity may negatively impact polyp detection and should be monitored for quality. Reasons for this unwarranted variation require investigation.

* Present affiliation NHS Forth Valley, Stirling, United Kingdom

Linda Sharp and Matthew D. Rutter are joint senior authors.

NED-APRIQOT study team listed in Acknowledgments

Supplementary Material

Publication History

Received: 17 March 2023

Accepted after revision: 26 October 2023

Accepted Manuscript online:
21 November 2023

Article published online:
08 February 2024

© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

  • References

  • 1 Beaton D, Sharp L, Trudgill NG. et al. UK endoscopy workload and workforce patterns: is there potential to increase capacity? A BSG analysis of the National Endoscopy Database. Frontline Gastroenterol 2022; 14: 103-110
  • 2 Richards M. Diagnostics: recovery and renewal – report of the independent review of diagnostic services for NHS England. NHS England, 2020. Accessed: Mar 17 2022.
  • 3 Norgine. Scope for change: what next for European colonoscopy services. 2017. Accessed Mar 17 2023.
  • 4 Ravindran S, Thomas-Gibson S, Bano M. et al. The national census of UK endoscopy services 2021. Frontline Gastroenterol 2022; 13: 463-470
  • 5 Shenbagaraj L, Thomas-Gibson S, Stebbing J. et al. Endoscopy in 2017: a national survey of practice in the UK. Frontline Gastroenterol 2019; 10: 7-15
  • 6 Ravindran S, Bassett P, Shaw T. et al. National census of UK endoscopy services in 2019. Frontline Gastroenterol 2021; 12: 451-460
  • 7 Oats B. Getting it Right First Time (GIRFT) GIRFT Programme National Specialty Report. Accessed Mar 17 2022.
  • 8 Kaminski MF, Regula J, Kraszewska E. et al. Quality indicators for colonoscopy and the risk of interval cancer. N Engl J Med 2010; 362: 1795-1803
  • 9 Corley DA, Jensen CD, Marks AR. et al. Adenoma detection rate and the risk of colorectal cancer and death. N Engl J Med 2014; 370: 1298-1306
  • 10 Spada C, Koulaouzidis A, Hassan C. et al. Colonoscopy quality across Europe: a report of the European Colonoscopy Quality Investigation (ECQI) Group. Endosc Int Open 2021; 9: E1456-E1462
  • 11 Kaminski MF, Thomas-Gibson S, Bugajski M. et al. Performance measures for lower gastrointestinal endoscopy: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative. Endoscopy 2017; 49: 378-397
  • 12 Valori R, Cortas G, de Lange T. et al. Performance measures for endoscopy services: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative. Endoscopy 2018; 50: 1186-1204
  • 13 Siau K, Green JT, Hawkes ND. et al. on behalf of the Joint Advisory Group on Gastrointestinal Endoscopy. Impact of the Joint Advisory Group on Gastrointestinal Endoscopy (JAG) on endoscopy services in the UK and beyond. Frontline Gastroenterol 2019; 10: 93-106
  • 14 Burr NE, Derbyshire E, Taylor J. et al. Variation in post-colonoscopy colorectal cancer across colonoscopy providers in English National Health Service: population-based cohort study. BMJ 2019; 367: l6090
  • 15 Lapointe-Shaw L, Abushomar H, Chen X-K. et al. Care and outcomes of patients with cancer admitted to the hospital on weekends and holidays: a retrospective cohort study. J Natl Compr Canc Netw 2016; 14: 867-874
  • 16 Takagi H, Ando T, Umemoto T. et al. A meta-analysis of weekend admission and surgery for aortic rupture and dissection. Vasc Med 2017; 22: 398-405
  • 17 Chen Y-C, Armoiry X, Higenbottam C. et al. Magnitude and modifiers of the weekend effect in hospital admissions: a systematic review and meta-analysis. BMJ Open 2019; 9: e025764
  • 18 Farrow L, Hall A, Aucott L. et al. Does quality of care in hip fracture vary by day of admission?. Arch Osteoporos 2020; 15: 52
  • 19 Afify SA, Abo-Elazm OM, Bahbah II. et al. Weekend and evening planned colonoscopy activity: a safe and effective way to meet demands. Endosc Int Open 2021; 9: E1026-E1031
  • 20 Li L, Rothwell PM, Study OV. Biases in detection of apparent “weekend effect” on outcome with administrative coding data: population-based study of stroke. BMJ 2016; 353: i2648
  • 21 Ferguson J, Walshe K. The quality and safety of locum doctors: a narrative review. J R Soc Med 2019; 112: 462-471
  • 22 Lee TJ, Siau K, Esmaily S. et al. Development of a national automated endoscopy database: the United Kingdom National Endoscopy Database (NED). United European Gastroenterol J 2019; 7: 798-806
  • 23 Catlow J, Sharp L, Kasim A. et al. The National Endoscopy Database (NED) Automated Performance Reports to Improve Quality Outcomes Trial (APRIQOT) randomized controlled trial design. Endosc Int Open 2020; 8: E1545-E1552
  • 24 Amano T, Nishida T, Shimakoshi H. et al. Number of polyps detected is a useful indicator of quality of clinical colonoscopy. Endosc Int Open 2018; 6: E878-884
  • 25 Rees CJ, Thomas Gibson S, Rutter MD. et al. and British Society of Gastroenterology, the Joint Advisory Group on GI Endoscopy, the Association of Coloproctology of Great Britain and Ireland UK key performance indicators and quality assurance standards for colonoscopy. Gut 2016; 65: 1923-1929
  • 26 Lee TJW, Rutter MD, Blanks RG. et al. Colonoscopy quality measures: experience from the NHS Bowel Cancer Screening Programme. Gut 2012; 61: 1050-1057
  • 27 Brown H, Prescott R. Statistics in Practice. Applied mixed models in medicine. West Sussex UK: John Wiley & Sons; 2006
  • 28 Dong Z, Wang J, Chen Y. et al. Negative effects of endoscopists' fatigue on colonoscopy quality on 34,022 screening colonoscopies. J Gastrointestin Liver Dis 2021; 30: 358-365
  • 29 Teng TY, Khor SN, Kailasam M. et al. Morning colonoscopies are associated with improved adenoma detection rates. Surg Endosc 2016; 30: 1796-1803
  • 30 Marcondes FO, Gourevitch RA, Schoen RE. et al. Adenoma detection rate falls at the end of the day in a large multi-site sample. Dig Dis Sci 2018; 63: 856-859
  • 31 Lee TJW, Rees CJ, Blanks RG. et al. Colonoscopic factors associated with adenoma detection in a national colorectal cancer screening program. Endoscopy 2014; 46: 203-211
  • 32 Kelly MP, Barker M. Why is changing health-related behaviour so difficult?. Public Health 2016; 136: 109-116
  • 33 Neilson LJ, East JE, Rajasekhar PT. et al. Sustained colonoscopy quality improvement using a simple intervention bundle. Endoscopy 2020; 52: 285-292
  • 34 Bishay K, Causada-Calo N, Scaffidi MA. et al. Associations between endoscopist feedback and improvements in colonoscopy quality indicators: a systematic review and meta-analysis. Gastrointest Endosc 2020; 92: 1030-1040.e
  • 35 Catlow J, Bhardwaj-Gosling R, Sharp L. et al. Using a dark logic model to explore adverse effects in audit and feedback: a qualitative study of gaming in colonoscopy. BMJ Qual Saf 2022; 31: 704-715
  • 36 Schwarz S, Hornschuch M, Pox C. et al. Polyp detection rate and cumulative incidence of post-colonoscopy colorectal cancer in Germany. Int J Cancer 2022; 152: 1547-1555