Prevalence of Polyps Greater Than 9 mm in a Consortium of Diverse Clinical Practice Settings in the United States

Background & Aims: Colonoscopy is often performed with the goal of identification of patients with serious colon neoplasia. We determined the prevalence of colon masses or polyps greater than 9 mm on the basis of age, gender, race, and procedure indication in diverse clinical practice settings and compared occurrence in patients receiving colonoscopy for screening, surveillance, or evaluation of symptoms. Methods: We obtained patient demographics, procedure indication, and endoscopic findings from colonoscopy reports in the Clinical Outcomes Research Initiative data repository, which receives endoscopy reports from 73 diverse practice sites in the United States. A multivariate model was developed to measure risk variables for a mass or polyps >9 mm. Absolute risk was calculated in the model on the basis of the number needed to endoscope (NNE) to identify 1 patient with a mass or polyp >9 mm. Results: From 2000-2002, colonoscopies in 141,413 unique patients were analyzed. Sixty-nine percent of the reports came from private practice (nonacademic) settings. Increasing age, male gender, and black race were associated with increased risk of mass or polyps >9 mm. In the 50- to 59-year-old average-risk group, 28 women and 18 men would need to have screening colonoscopy to identify 1 patient with a mass/polyp >9 mm. Patients with positive fecal occult blood test results, hematochezia, and anemia had lower NNE, whereas men older than 60 years receiving adenoma surveillance and patients with irritable bowel symptoms had similar NNE compared with average-risk subjects. Conclusions: The prevalence of a colon lesion >9 mm varies on the basis of age, gender, race, and procedure indication. Understanding utilization and outcomes can lead to more optimal use of colonoscopy.