Quality Indicators for Colonoscopy

Douglas K Rex MD; Philip S Schoenfeld MD, MSEd, MSc (Epi); Jonathan Cohen MD; Irving M Pike MD; Douglas G Adler MD; M Brian Fennerty MD; John G Lieb MD; Walter G Park MD, MS; Maged K Rizk MD; Mandeep S Sawhney MD, MS; Nicholas J Shaheen MD, MPH; Sachin Wani MD; David S Weinberg MD, MSc


Am J Gastroenterol. 2015;110(1):72-90. 

In This Article

Abstract and Introduction


Colonoscopy is widely used for the diagnosis and treatment of colon disorders. Properly performed, colonoscopy is generally safe, accurate, and well-tolerated. Visualization of the mucosa of the entire large intestine and distal terminal ileum usually is possible during colonoscopy. Polyps can be removed during colonoscopy, thereby reducing the risk of colon cancer. Colonoscopy is the preferred method to evaluate the colon in most adult patients with large-bowel symptoms, iron deficiency anemia, abnormal results on radiographic studies of the colon, positive results on colorectal cancer (CRC) screening tests, post-polypectomy and post-cancer resection surveillance, and diagnosis and surveillance in inflammatory bowel disease. In addition, colonoscopy is the most commonly used CRC screening test in the United States.[1] Based on 2010 data, over 3.3 million outpatient colonoscopies are performed annually in the United States, with screening and polyp surveillance accounting for half of indications.[2]

Optimal effectiveness of colonoscopy depends on patient acceptance of the procedure, which depends mostly on acceptance of the bowel preparation.[3] Preparation quality affects the completeness of examination, procedure duration, and the need to cancel or repeat procedures at earlier dates than would otherwise be needed.[4,5] Ineffective preparation is a major contributor to costs.[6] Meticulous inspection[7,8] and longer withdrawal times[9–14] are associated with higher adenoma detection rates (ADR). A high ADR is essential to rendering recommended intervals[15] between screening and surveillance examinations safe.[16,17] Optimal technique is needed to ensure a high probability of detecting dysplasia when present in inflammatory bowel disease.[17–21] Finally, technical expertise and experience will help prevent adverse events that might offset the benefits of removing neoplastic lesions.[22]

Recent studies report that colonoscopy is less effective in preventing proximal colon cancer and cancer deaths (ie, colon cancer proximal to the splenic flexure) compared with distal cancer (ie, colon cancer at or distal to the splenic flexure).[23–28] Decreased protection against right-sided CRC is likely due to multiple factors. These include missed adenomas or incompletely resected adenomas; suboptimal bowel preparation; precancerous lesions that are endoscopically subtle or difficult to remove, such as sessile serrated polyps and flat and/or depressed adenomas, and differences in tumorigenesis between right-sided and left-sided cancers. Improving prevention of right-sided colon cancer is a major goal of colonoscopy quality programs.

Five studies have established that gastroenterologists are more effective than surgeons or primary care physicians at preventing CRC by colonoscopy.[27,29–32] This most likely reflects higher rates of complete examinations (ie, cecal intubation)[30] and higher rates of adenoma detection among gastroenterologists.[33,34] All endoscopists performing colonoscopy should measure the quality of their colonoscopy. Institutions where endoscopists from multiple specialties are practicing should reasonably expect all endoscopists to participate in the program and achieve recommended quality benchmarks.

The quality of health care can be measured by comparing the performance of an individual or a group of individuals with an ideal or benchmark.[35] The particular parameter that is being used for comparison is termed a quality indicator. A quality indicator often is reported as a ratio between the incidence of correct performance and the opportunity for correct performance[4] or as the proportion of interventions that achieve a predefined goal.[35] Quality indicators can be divided into 3 categories: (1) structural measures—these assess characteristics of the entire health care environment (eg, participation by a physician or other clinician in systematic clinical database registry that includes consensus endorsed quality measures), (2) process measures—these assess performance during the delivery of care (eg, ADR and adequate biopsy sampling during colonoscopy for chronic ulcerative colitis), (3) outcome measures—these assess the results of the care that was provided (eg, the prevention of cancer by colonoscopy and reduction in the incidence of colonoscopic perforation).