2012-01-27 16:05:47 UTC

What Are the Benchmarks for “Quality Colonoscopy”?

Jan. 27, 2012


Philip Schoenfeld, MD, MSED, MSC (EPI)

Associate Professor of Medicine; Director, Training Program in Gastrointestinal Epidemiology, University of Michigan School of Medicine, Ann Arbor


Every endoscopist strives to reach the cecum and identify and remove adenomas when performing colonoscopy for colorectal cancer (CRC) screening. However, when our professional societies make recommendations about indicators of high-quality colonoscopy, it is inadequate to simply state that cecal intubation rates and adenoma detection rates (ADRs) should be high. Numerical benchmarks for each quality indicator are needed to differentiate high-performing endoscopists from underperformers. For example, is an ADR of 25 percent appropriate? That is a judgment call right now. We need better research in order to issue evidence-based numerical benchmarks that define high-quality colonoscopy.

What are the other problems with quality indicators? First, we need to define appropriate mechanisms for measuring quality indicators. Using the example of cecal intubation rates, endoscopists could record separate photographs of the appendiceal orifice and the ileocecal valve. That could be sufficient, but you may find it much more difficult to define measurement of ADRs. Second, what to do when we identify an underperformer? It won’t be very helpful to identify these underperforming endoscopists unless we have effective quality improvement programs too.

As Douglas O. Faigel, MD, AGAF, states, cecal intubation rates and ADRs are good indicators of quality colonoscopy, but we shouldn’t limit ourselves to these quality measures. Other quantifiable outcomes also define high-quality colonoscopy, including rates of serious complications (e.g., perforation and post-polypectomy bleeding) and adherence to guideline recommendations for timing of repeat colonoscopy.1

Cecal intubation rates

This is the easiest indicator to support based on available data. A large database study from Ontario, Canada demonstrated that higher cecal intubation rates are associated with greater protection against colon cancer in the right side of the colon.2Another database study from the U.K. confirms that higher cecal intubation rates are associated with higher ADRs.3 The U.S. Multi-Society Task Force on Colorectal Cancer stated that cecal intubation rates should exceed 95 percent for screening and surveillance procedures. Proving cecal intubation is relatively straightforward — simply photograph the appendiceal orifice and ileo-cecal valve. The thornier issue is development of a quality improvement program for an underperforming endoscopist. Although Dr. Faigel’s suggested interventions sound reasonable, we don’t have any data that they change cecal intubation rates.


Higher ADRs are clearly associated with fewer right-sided CRCs and fewer interval cancers. So, what is an appropriate ADR? Is it 20 percent? Is it 25 percent? Is this for screening colonoscopies or should surveillance colonoscopies be included too? These questions and others about measurement of ADRs have not been answered satisfactorily by research data. Multiple approaches have been suggested, including “adenomas under curve,” which account for detecting multiple adenomas in a single colonoscopy, and adenomas per colonoscopy stratified by age of patient, gender of patient and indication (e.g., screening versus surveillance). However, simply stating that adenomas should be identified in 25 percent of men and 15 percent of women undergoing screening colonoscopies is a bare minimum to identify “adequate” quality colonoscopy.

Measuring ADR isn’t complicated, but it is cumbersome. I reject the idea that polyp detection rate is an appropriate surrogate marker for ADR (although it is convenient to simply use endoscopy reports to generate a polyp detection rate). Instead, we will need to track pathology reports about polyp histology and develop appropriate computer programs to include polyp histology in endoscopy reporting systems.

If an endoscopist has a low ADR, then how can we identify the root causes of this poor performance? You could start with withdrawal time. Per the work of Barclay and colleagues, “as compared with colonoscopists with mean withdrawal times of less than six minutes, those with mean withdrawal times of six minutes or more had higher [ADRs] … (28.3 percent versus 11.8 percent, P<0.001).”4 So, short (less than six minutes) withdrawal times are associated with lower ADRs. However, although it should be recorded, withdrawal time should not be a quality measure. For example, if an endoscopist has a withdrawal time of five minutes and an ADR of 35 percent, then the low withdrawal time does not indicate poor performance. Withdrawal time is helpful when underperformers with low ADRs are also found to have short withdrawal times. These poor performers may be trained to increase withdrawal time in each segment of the colon and improve ADRs.5

You should also quantify the quality of bowel preparation. Sub-optimal bowel cleansing is associated with lower ADRs.6 If an underperforming endoscopist routinely reports “fair” bowel preparation, then ensure that the endoscopist “splits” the prep for all patients, making them consume part of the purgative on the day of colonoscopy. “Split” preps are associated with higher rates of optimal bowel preparation and higher ADRs.7

Unfortunately, other interventions for underperformers have not been proven effective, as elegantly reviewed by Corley et al.8

Colonoscopy complication rates

Quality colonoscopy should be associated with very low rates of colon perforation, post-polypectomy bleeding and other serious adverse events. Unfortunately, appropriate benchmarks for complication rates are difficult to quantify and are even more difficult to measure.

a “lexicon” for defining and measuring adverse events, but did not provide specific numerical benchmarks for immediate and delayed (14-day post-procedure) complications.9 So, what is an acceptable rate of colon perforation? Informed consents may quote a perforation rate of 1/1,000. However, a recent meta-analysis of prospective studies reported perforation rates of approximately 1/6,000 for diagnostic colonoscopies (i.e., no intervention or only use of cold forceps) and approximately 1/1,500 for therapeutic colonoscopies (i.e, snare polypectomy or “hot” forceps polypectomy).10

A tougher problem may be measuring complication rates. First, since complications should be rare, a single severe complication may artificially inflate an endoscopist’s complication rate. Thus, data on severe complications (e.g., perforation or post-polypectomy bleeding) must be tracked over multiple years. Second, it is difficult to measure/document complications that occur after the patient leaves the endoscopy unit. Therefore, the ASGE working group recommended a 14-day window to identify severe complications such as hospitalization.10 This requires follow-up with each colonoscopy patient after 14 days. If a severe complication like hospitalization has occurred, then you’d like to determine if the complication was related to the colonoscopy. Without better metrics, how can we even identify endoscopists who need a quality improvement (QI) program to reduce complications? 

Repeat colonoscopy guidelines

If endoscopists routinely tell patients to return for repeat screening/surveillance colonoscopy sooner than recommended by guidelines, then the cost-effectiveness of colonoscopy for CRC screening is lost and we subject patients to the risks and inconveniences of colonoscopy more often than necessary. Recent studies demonstrate that patients are frequently told to return for screening/surveillance colonoscopy sooner than recommended.11-13

Measurement of adherence to guideline recommendations will also be cumbersome because appropriateness of timing for repeat colonoscopy can only be determined after review of polyp histology. Although there is no data about QI programs for adherence to these guideline recommendations, sub-optimal bowel preparation12, 13 is the factor most commonly associated with these inappropriate recommendations. Fear of malpractice and lack of financial incentives to adhere to guidelines may also play a role, so there are interventions that could be examined in future research.14


Although I’ve identified different stumbling blocks, we should measure indicators of quality colonoscopy. This is the right thing to do for patients. Also, reporting quality indicators to CMS for multiple disorders, including CRC screening, will make gastroenterologists eligible for a small (0.5 percent) bonus for all Medicare Part B service charges in 2012. However, CMS may make this requirement punitive in 2015 with a 1.5 percent cut in reimbursement fees and a 2 percent cut in 2016 for physicians who fail to report. Furthermore, surpassing numerical benchmarks may be factored into a formula that will further impact reimbursement.

Now, let’s get started on better research to set numerical benchmarks for each quality indicator, define ways to measure these indicators and define effective quality improvement programs for underperformers.

Dr. Schoenfeld is on the advisory board of Forest Laboratories, Ironwood Pharmaceuticals and Salix Pharmaceuticals, and has given lectures under the direct sponsorship of Salix Pharmaceuticals. He is also a member of ACG’s Educational Affairs Committee.

1. Levin, B., et al., Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology 2008. 134(5): p. 1570-95.
2. Baxter NN, Sutradhar R, Forbes SS, Paszat LF, Saskin R, Rabeneck L. Analysis of administrative data finds endoscopist quality measures associated with postcolonoscopy colorectal cancer. Gastroenterology 2011;140:65-72.
3. Lee TJ, Rutter MD, Blanks RG, et al. Colonoscopy Quality Measures: Experience from the NHS Bowel Cancer Screening Programme. Gut 2011. Epub published Sept 22, 2011.
4. Barclay RL, Vicari JJ, Doughty AS, Johanson JF, Greenlaw RL. Colonoscopic withdrawal times and adenoma detection during screening colonoscopy. New Engl J Med 2006;355:2533-41.
5. Barclay RL, Vicari JJ, Greenlaw RL. Effect of a time-dependent colonoscopic withdrawal protocol on adenoma detection during screening colonoscopy. Clin Gastroenterol Hepatol 2008;6:1091-8.
6. Lebwohl, Kastrinos F, Glick M, et al. The impact of sub-optimal bowel preparation on ADRs and the factors associated with early repeat colonoscopy. Gastrointest Endosc 2011; 73: 1207-14.
7. Cohen LB, Sanyal SM, Von Althann C, et al. Clinical Trial: 2-L polypethylene glycol-based lavage solutions for colonoscopy preparation-a randomized, single-blind study of two formulations. Aliment Pharmacol Ther 2010; 32: 637-44.
8. Corley DA, Jensen CD, Marks AR. Can we improve ADRs? A systematic review of intervention studies. Gastrointest Endosc 2010; 74: p. 656-65.
9. Cotton PB, Eisen GM, Aabakken L, et al. A lexicon for endoscopic adverse events: Report of an ASGE workshop. Gastrointest Endosc 2010; 71(3):446-54.
10. Fehmi SA, Chokshi N, Schoenfeld P, et al. Risk of perforation during colonoscopy: A systematic review and meta-analysis. Gastroenterology 2009; A210.
11. Saini S, Nayak R, Bernard L, Schoenfeld P. Why don’t gastroenterologists follow colon polyp surveillance guidelines? Results of a national survey. J Clin Gastro 2009; 43(6):554-558.
12. Menees S, Elliott EE, Schoenfeld PS, et al. The impact of colonoscopy preparation on recommended colonoscopy screening intervals in average-risk screening patients with no polyps. Gastroenterology 2011; pg 871, #Tu1412.
13. Anastassiades CP, Elliott E, Menees S, Schoenfeld P, et al. The impact of bowel preparation quality on recommended surveillance colonoscopy in average-risk patients with 1-2 small polyps. Am J Gastroenterol 2011; 106; A1514.
14. Rubenstein J, Saini S, Schoenfeld P, et al. Influence of malpractice history on the practice of screening and surveillance for Barrett’s esophagus. Am J Gastroenterol 2008; 103(4):842-9.

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