Predictors of Adenoma Detection in Colonoscopy by Gastroenterologists and General Surgeons

B Evans, M Borgaonkar, MD, FRCPC, D Pace, MD, FRCSC, N Hickey, M O’Leary, G Fallows, J McGrath. Memorial University of Newfoundland, Queens University.

Introduction: Adenoma detection rate (ADR) is a major indicator of colonoscopy quality. This study looks at predictors of adenoma detection.
Purpose: To identify factors that are associated with adenoma detection in patients who undergo colonoscopy.
Methods: This retrospective cohort study was performed on adults who underwent colonoscopy in the city of St. John’s, Canada, in the year 2012. Subjects were identified through records from the health authority. Data were extracted from the electronic medical record (EMR), including both the endoscopist and nursing procedure reports. Data were recorded on a standardized data sheet and entered into SPSS version 20.0 for analysis. Univariate analysis was used to identify variables associated with adenoma detection (p<0.10) and multivariate logistic regression was used to identify variables independently associated with adenoma detection (p<0.05). Student’s T-test and ANOVA were used for continuous variables and Chi-squared test for categorical variables. An adenoma was defined as a lesion classified histologically as any of the following: adenoma, adenoma with carcinoma, sessile serrated adenoma/polyp, serrated adenoma, serrated adenoma with dysplasia, traditional serrated adenoma.

Results: Complete data were collected on 2001 colonoscopies. Twenty-nine were excluded due to missing reports. Mean patient age was 59.4 years (± 11.6) with 1124 (57.0%) females. The most common indication for colonoscopy was family history of colorectal cancer in 510 (25.9%) patients. A Gastroenterologist performed 1293 colonoscopies (66%) and a General Surgeon performed 679 (34%). A total of 8 Gastroenterologists and 14 Surgeons were studied. Overall ADR was 21.9%.
In univariate analysis, mean age was higher in patients who had adenomas compared to those without (61.4 years vs. 57.4 years; p<0.001). Adenomas were found more frequently in men than women (27.2% vs. 17.9%; p<0.001) and in patients with histologically confirmed colorectal cancer (CRC) (40.4% vs. 21.5%; p=0.002).
ADR was associated with the endoscopist performing the procedure (Range:10.5%-50.0%; p<0.001). ADR was associated with the procedure indication (Range:4.9%-35.4%, p<0.001), with the highest rates seen in: personal history of polyps, abnormal colonic imaging and anemia/fecal occult blood positive (35.4%, 33.3% and 26.1%, respectively). The nurse assisting with the procedure was also associated with ADR (Range:13.2%-50%; p=0.003).
In multivariate analysis, variables independently associated with ADR included gender (OR=1.79), age (OR=1.03), histologically confirmed CRC (OR=2.65), indication (p<0.001), endoscopist (p=0.002), and nurse (p=0.021). Indications most strongly associated include: abnormal colonic imaging, personal history of polyps and rectal bleed. Two endoscopists and 2 nurses had significantly higher ADRs when compared to the lowest detectors.

Conclusions: Adenomas were detected more frequently in male patients, patients of increasing age, patients with CRC and for a number of indications. Two endoscopists and two nurses had statistically significantly greater ADRs than the lowest detectors.

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