From the AGA Journals

Simpler method of adenoma detection rate might be possible, study suggests



Using the adenoma detection rate (ADR) for all colonoscopies could be just as good as using the more traditional ADR approach of using only colonoscopies that are performed for screening purposes, a new paper suggests.

The findings, published earlier this year in Gastroenterology, point to a potentially simpler approach to the ADR, an established colonoscopy quality metric that measures the percentage of colonoscopies in which at least one adenoma was found, the researchers said, because of the complexities posed by separating out screening colonoscopies from those for other indications.

“Methods for ascertaining colonoscopy indication include manual review, electronic medical record queries, and text string searches of colonoscopy reports, which are resource-intensive and subject to misclassification,” said the researchers, led by Douglas Corley, MD, PhD, MPH, and Christopher Jensen, PhD, researchers at Kaiser Permanente Northern California. “These barriers have impeded the universal adoption of screening ADR reporting and suggest the need for a simpler, valid alternative to screening ADR.”

The analysis included Kaiser Permanente Northern California, Kaiser Permanente Southern California, Kaiser Permanente Washington, and the University of Texas Southwestern’s Parkland Memorial Hospital – large, demographically diverse, community-based health systems with 45 endoscopy centers and covering about 3% of the U.S. population. The data that were assessed covered 487 endoscopists who performed 1,046,916 cancer-negative colonoscopies from January 2011 to June 2019.

The median overall ADR was 36.3%; the median screening, ADR 29.7%; the diagnostic ADR, 37.1%; and the surveillance ADR, 48.6%.

No matter the colonoscopy indication, the researchers found, ADRs were similarly inversely related to the risk of post-colonoscopy colorectal cancer (PCCRC) rate. For patients of physicians with ADRs of 45% or more, using the group with a less than 25% ADR as the reference group, the risk hazard ratio for the overall ADRs was 0.44, and for the screening ADRs, it was 0.43.

Researchers also found that the quartile of overall ADR had a similar overall predictive ability for PCCRC to the quartile of screening ADR – both with a C-statistic of 0.71.

The overall ADR did just about as well as the screening ADR in identifying physician performance quartile groupings – especially in the case of the lowest quartile. Among the 293 endoscopists who performed colonoscopies in 2017-2018, for instance, 62 of the 73 providers who were in the lowest quartile for screening ADR were also in the lowest quartile for the overall ADR, the researchers found. And there were no providers who differed by more than one quartile.

When considering all quartiles, 69.6% of endoscopists had identical quartile rankings for overall ADR and screening ADR, 29.4% differed by one quartile, and only 1% differed by two quartiles.

The inclination to use screening colonoscopies to compute ADR metrics was intended to promote uniformity in the field, but this might not be the best practice, the researchers suggest.

“Given the large differences in screening ADRs between settings and the potential for indication misclassification, it is not clear that restricting ADR calculations to screening colonoscopies allows for a more ‘apples-to-apples’ comparison across settings than methods that include all colonoscopies,” they said. “The current study found that overall ADR as a quality metric performed similarly to screening ADR for predicting PCCRC and identifying the same providers in the lowest quartile. In addition, it is simpler to calculate, not susceptible to indication misclassification or potential provider-related biases, and more precise because it includes many more colonoscopies.”

In an editorial that was published in Gastroenterology, Jill Tinmouth, MD, PhD, University of Toronto, and Catherine Dubé, MD, University of Ottawa, noted that measuring ADR is valuable only if it improves the quality of colonoscopies.

“Ultimately, this new approach to measuring ADR and identifying underperformance is only valuable if it leads to improvement in colonoscopy quality. The approach proposed by Corley et al. should make it easier for facilities, screening programs, and jurisdictions to measure ADR, and this is an important first step. However, to move the dial on quality, reporting ADR needs to be accompanied by physician uptake of strategies to improve their colonoscopy performance, that is, split-dose bowel preparation, proper insertion and withdrawal techniques ([e.g.], careful cleaning and inspection and turning the patient, when possible), and improved polypectomy skills,” they wrote.

The authors disclosed no conflicts of interest.

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