Letter to the Editor

Evaluation of preparation methods for colonoscopy

Kris Acebedo, Ravi Thiruvengadam MD

Riverside, California, USA

Available online 12 February 2021.

https://doi.org/10.1016/j.gie.2020.09.026

Gastrointestinal Endoscopy, Volume 93, Issue 3, March 2021, Pages 775

To the Editor:

The meta-analysis by Zhang et al (1). has important implications given the crucial role preparation plays in ensuring a high-quality colonoscopy(2). Scales of cleanliness are at their core subjective, validation studies (which had relatively low adenoma detection rates [ADRs](3) notwithstanding. We suggest that comparison of cleaning methods would be more objective and valid if ADRs (and right-sided serrated polyp detection rates) in routine first-time average- risk screening colonoscopies were used as dependent variables, with the proviso that the ADRs of the performing colonoscopists be high—we would suggest in excess of 50% (the prevalence of adenomas in average-risk persons is probably over 60%(4,5). This would be the best way to determine whether a particular preparation variant resulted in “adequate bowel preparation.” We would also suggest that comparison groups have at least 500 examinations each to have reliable data(6).Although a study of 1000 patients might seem like a high number, given that by one estimate, 19 million colonoscopies (a substantial portion are likely first-time screening examinations) are performed in the United States every year, studies of this nature are not only eminently feasible(7), they are essential lest conclusions like those arrived at in this article and other laudable efforts at making colonoscopies easier on patients result in poorer-quality examinations. In this meta-analysis, only 4 studies presented data on adenoma detection in screening colonoscopies and 9 did not report data on adenoma detection at all. In consequence, we would suggest caution in altering practice based on its conclusions.

Disclosure

All authors disclosed no financial relationships.

References

1. X. Zhang, Q. Wu, M. Wei, et al. Low-residual diet versus clear-liquid diet for bowel preparation before colonoscopy: meta-analysis and trial sequential analysis of randomized controlled trials Gastrointest Endosc, 92 (2020), pp. 508-518.

2. A.M. Soweid, A.A. Kobeissy, F.R. Jamali, et al.
A randomized single-blind trial of standard diet versus fiber-free diet with polyethylene glycol electrolyte solution for colonoscopy preparation
Endoscopy, 42 (2010), pp. 633-638
3. E.J. Lai, A.H. Calderwood, G. Doros, et al.
The Boston bowel preparation scale: a valid and reliable instrument for colonoscopy- oriented research
Gastrointest Endosc, 69 (2009), pp. 620-625

4. G.S. Raju, V. Vadyala, R. Slack, et al.
Adenoma detection in patients undergoing a comprehensive colonoscopy screening Cancer Med, 2 (2013), pp. 391-402

5. R. Thiruvengadam, E.E. Yung, J.M. Smith, et al.
70% of average-risk persons of screening age have colon adenomas - ADR in a community cohort with biopsies read by academic GI pathologists [abstract] Gastrointest Endosc, 85 (2017), pp. AB394-AB395

6. A. Do, J. Weinberg, A. Kakkar, et al.
Reliability of adenoma detection rate is based on procedural volume Gastrointest Endosc, 77 (2013), pp. 376-380

7. iData Research. https://idataresearch.com/an-astounding-19-million-colonoscopies-are- performed-annually-in-the-united-states/. Accessed October 21, 2020.