Colonoscopy is an excellent area for quality improvement because it is high volume, has significant associated risk and expense, and there is evidence that variability in its performance affects outcomes. The best end point for validation of quality metrics in colonoscopy is colorectal cancer incidence and mortality, but a more readily accessible metric is the adenoma detection rate. Fourteen quality metrics were proposed in 2006, and these are described in this article. Implementation of quality improvement initiatives involves rapid assessments and changes on an iterative basis, and can be done at the individual, group, or facility level.
Key points
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Quality in colonoscopy is essential to maintaining the trust of patients and the public.
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Several metrics have been suggested as quality indicators, including appropriate screening/surveillance intervals, adenoma detection rates, cecal intubation rates, and appropriate documentation.
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Implementation of quality improvement projects requires identification of a problem and outcome for measurement and development of an intervention followed by frequent short-term assessments and adjustments.
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The electronic health records and other registries facilitate quality reporting and measurement.
Introduction to quality
Keen interest in quality within medicine began after the Institute of Medicine’s report on medical errors was published in 2000. This report described the landscape of medicine at the time in the United States and revealed, for example, that 44,000 to 98,000 Americans die each year from medical errors. This report, along with public opinion regarding current care in the United States, led to a national call for reform within medicine. The report listed the major quality domains as safety, practice consistent with present medical knowledge, and customization.
Many parties have a stake in the measurement and reporting of quality. Stakeholders include patients, providers, professional societies, payors, regulatory bodies and accrediting organizations, the National Quality Forum, and the Centers for Medicare and Medicaid Services. Most stakeholders agree that the goal is to improve outcomes and avoid unintended consequences. There are financial incentives for providers to report quality measures and, as of 2015, there will be financial penalties for failing to report within Medicare.
Given this landscape, colonoscopy is an excellent area for quality improvement work for several reasons. First, colonoscopy is the most common endoscopic procedure in United States and there is significant associated risk and expense. Second, standardized reporting of colonoscopies has been advocated, but evidence exists that performance of colonoscopy varies and this variation may affect effectiveness. Publication of the joint American Society for Gastrointestinal Endoscopy/American College of Gastroenterology “Quality Indicators for Colonoscopy” in 2006 highlighted the importance of quality issues within colonoscopy and provided tangible benchmarks for achievement. The importance of ensuring the highest quality in colonoscopy is further promoted by several recent studies questioning the effectiveness of colonoscopy in reducing colorectal cancer (CRC) mortality, especially from right-sided lesions.
Before discussing quality in colonoscopy, it is important to emphasize the distinction between clinical guidelines and quality indicators. The former relates to recommendations for clinical care often related to a specific condition or work-up of a particular symptom. Guidelines may be supported by varying degrees of evidence, ranging from randomized controlled trials to expert opinion. In contrast, quality indicators are concrete, measurable items related either to the process of care in which the receipt of medical services is tracked (eg, whether the cecum was reached and photodocumented with landmarks) or outcome measures (eg, whether a cancer was diagnosed within 3 years of colonoscopy), which in part reflect the results of medical care.
Introduction to quality
Keen interest in quality within medicine began after the Institute of Medicine’s report on medical errors was published in 2000. This report described the landscape of medicine at the time in the United States and revealed, for example, that 44,000 to 98,000 Americans die each year from medical errors. This report, along with public opinion regarding current care in the United States, led to a national call for reform within medicine. The report listed the major quality domains as safety, practice consistent with present medical knowledge, and customization.
Many parties have a stake in the measurement and reporting of quality. Stakeholders include patients, providers, professional societies, payors, regulatory bodies and accrediting organizations, the National Quality Forum, and the Centers for Medicare and Medicaid Services. Most stakeholders agree that the goal is to improve outcomes and avoid unintended consequences. There are financial incentives for providers to report quality measures and, as of 2015, there will be financial penalties for failing to report within Medicare.
Given this landscape, colonoscopy is an excellent area for quality improvement work for several reasons. First, colonoscopy is the most common endoscopic procedure in United States and there is significant associated risk and expense. Second, standardized reporting of colonoscopies has been advocated, but evidence exists that performance of colonoscopy varies and this variation may affect effectiveness. Publication of the joint American Society for Gastrointestinal Endoscopy/American College of Gastroenterology “Quality Indicators for Colonoscopy” in 2006 highlighted the importance of quality issues within colonoscopy and provided tangible benchmarks for achievement. The importance of ensuring the highest quality in colonoscopy is further promoted by several recent studies questioning the effectiveness of colonoscopy in reducing colorectal cancer (CRC) mortality, especially from right-sided lesions.
Before discussing quality in colonoscopy, it is important to emphasize the distinction between clinical guidelines and quality indicators. The former relates to recommendations for clinical care often related to a specific condition or work-up of a particular symptom. Guidelines may be supported by varying degrees of evidence, ranging from randomized controlled trials to expert opinion. In contrast, quality indicators are concrete, measurable items related either to the process of care in which the receipt of medical services is tracked (eg, whether the cecum was reached and photodocumented with landmarks) or outcome measures (eg, whether a cancer was diagnosed within 3 years of colonoscopy), which in part reflect the results of medical care.
Quality in colonoscopy
When quality metrics are developed, consideration is given to the end point by which the metric(s) can be monitored and validated. What is the best end point for validation of quality metrics in colonoscopy? CRC incidence and mortality are arguably the most relevant and important outcome in performance of colonoscopy and, as such, ideally would be the end point by which to validate metrics. However, these end points are difficult to measure and, because of low incidence, require many person-years of follow-up to yield meaningful results. Years of data collection are not often feasible in the quality work in which data collection, results, and adjustments are made more rapidly than in classic clinical research. Another end point is the incidence of so-called interval cancers, which are CRCs that arise within a certain time frame after colonoscopy. These interval cancers may arise from missed or incompletely removed lesions at initial colonoscopy, but may also be caused by biologically aggressive tumors that arise de novo. Interval CRCs can be measured in 2 different ways. One is a prospective evaluation after colonoscopy with removal of polyps of patients who are enrolled in a surveillance program and return for a follow-up colonoscopy. A second way uses a case-control design in which patients with CRC are identified and assessed for whether or not they had a prior colonoscopy within 3 years of diagnosis. Because of the resources, time, and large numbers necessary to measure interval CRCs, a more readily accessible metric is the adenoma detection rate (ADR). ADR has gained international acceptance as a quality indicator and is discussed in detail later. In addition, patient satisfaction is also an important metric for consideration, but may be challenging to interpret because of variation in patient population and other factors difficult to control for at the endoscopist level.
Colonoscopy quality metrics
Most colonoscopy quality metrics are process measures rather than outcome measures and occur at the level of the endoscopist rather than the endoscopy unit or hospital. The American Society of Gastrointestinal Endoscopy/American College of Gastroenterology Task Force on Quality Indicators for Colonoscopy proposed 14 quality metrics that occur at the preprocedure, intraprocedure, and postprocedure phases of colonoscopy ( Table 1 ). Only 2 measures have strong recommendations (appropriate indication and use of recommended postpolypectomy and postcancer resection surveillance intervals) and 4 have intermediate recommendations (cecal intubation rates, ADR, inflammatory bowel disease [IBD] surveillance biopsies, and endoscopic management of postpolypectomy bleeding). This article highlights several of these indicators in decreasing order of strength of recommendation and provides background information on the measure, including whether the literature supports its association with improved outcomes.
| Quality Indicator | Grade of Recommendation |
|---|---|
| Preprocedure Indicators | |
| Appropriate indication | 1C+ |
| Informed consent including discussion of risks | 3 |
| Use of postpolypectomy and postcancer resection surveillance intervals | 1A |
| Use of IBD disease surveillance intervals | 2C |
| Documentation of quality of bowel preparation in note | 2C |
| Intraprocedure Indicators | |
| Cecal intubation rates including photographic documentation of landmark in note | 1C |
| Adenoma detection during screening | 1C |
| Withdrawal time: mean >6 min in normal examinations | 2C |
| Biopsy specimens in patients with chronic diarrhea | 2C |
| Number and distribution of biopsy specimens in IBD surveillance | 1C |
| Endoscopic resection attempted for pedunculated polyps and sessile polyps <2 cm | 3 |
| Postprocedure Indicator | |
| Incidence of perforation | 2C |
| Incidence of postpolypectomy bleeding | 2C |
| Postpolypectomy bleeding managed nonoperatively | 1C |
Screening/Surveillance Intervals
The use of recommended screening intervals for normal colonoscopies and recommended postpolypectomy and postcancer surveillance intervals for those with neoplasia is important to minimize risks of excessive procedures and maximize cost-effectiveness of population-based screening. Ample literature suggests that patients are told to return more frequently than is dictated by guidelines. However, those who are deemed high risk who do not return for surveillance also indicate poor-quality care. In one study, 34% of those with polyps greater than 1 cm did not return for surveillance. In another study of patients with adenomas or CRC, 35% had no follow-up and 38% had their follow-up delayed.
The importance of appropriate polyp surveillance and avoidance of inappropriate use has been recognized at the national level with the endorsement of colonoscopy interval quality measures by the National Quality Forum and their adoption by the Physician Quality Reporting System (PQRS). PQRS was initiated in 2007 by the Centers for Medicare and Medicaid Services (CMS) as a reporting program that uses “a combination of incentive payments and payment adjustments to promote reporting of quality information by eligible professionals.” Those who report satisfactorily on the measure receive incentive payments based on their Medicare Part B fee charges. Starting in 2015, there will also be a payment penalty for those who do not satisfactorily report data on quality measures for covered professional services.
Of the 190 measures included in the 2011 PQRS measurements, only 1 pertained to colonoscopy. Measure 185, “Endoscopy & Polyp Surveillance: Colonoscopy Interval for Patients with a History of Adenomatous Polyps – Avoidance of Inappropriate Use” specifies reporting of the percentage of patients aged 18 years and older receiving a surveillance colonoscopy and a history of colonic polyp(s) in a previous colonoscopy who had a follow-up interval of 3 or more years since their last colonoscopy documented in the colonoscopy report. Detailed measure specifications can be found at http://www.cms.gov/Medicare/Quality-Initiatives-Patient-Assessment-Instruments/PQRS/downloads/2011_physqualrptg_measurespecificationsmanual_033111.pdf .
There is no performance threshold yet set for this measure, and providers receive credit simply for reporting their performance scores.
ADR
Detecting and removing adenomas is a fundamental goal of screening colonoscopy. Missed lesions are a potential cause of interval cancers and perhaps the lower than expected protection rate from colonoscopy. Despite its importance, there are large disparities in the detection rates of practicing endoscopists, which has been shown in studies of tandem colonoscopy, small group practices, missed neoplasia, and computed tomography colonography. The target rate for ADR is greater than or equal to 25% in men and greater than or equal to 15% in women more than 50 years old presenting for average-risk screening based on observed prevalence rates of neoplasia in the United States.
Measurement of ADR should be a priority. The most accepted method for measurement is calculation of the number of screening colonoscopies in which at least 1 adenoma was found divided by the total number of screening colonoscopies performed. Others have suggested the mean number of adenomas per patient as another calculation that may add additional information. To calculate mean adenomas per patient, the total number of adenomas is divided by the total number of colonoscopies performed. Although mean adenoma per patient may prove to be a good measure of adenoma detection, current data are insufficient to establish compliance rate benchmarks for its use as a quality metric.
The type of examinations and the time period or volume over which ADR should be calculated has not been confirmed. For now, ADR should be limited to screening colonoscopy examinations, although, as more data emerge on adenoma rates in surveillance colonoscopy, surveillance may be monitored as well, whether in combination with screening or independently. The time period or number of cases over which ADR is calculated is not specified, which may cause difficulty in interpreting results, especially for low-volume endoscopists. One study highlights the importance of the number of procedures over which this measure is calculated because low numbers may not accurately represent the ADR ( Table 2 ). At least 500 procedures need to be included in the calculation to have a reliable point estimate of ADR and a 95% confidence interval can account for uncertainty and should be used in the setting of lower numbers of procedures to help interpret endoscopist performance.
| # of Colonoscopies | ADR | |||||
|---|---|---|---|---|---|---|
| 15% | 20% | 25% | 30% | 35% | 40% | |
| 100 | 8–22 | 12–28 | 17–33 | 21–39 | 26–44 | 30–50 |
| 500 | 12–18 | 16–24 | 21–29 | 26–34 | 31–39 | 36–44 |
| 1000 | 13–17 | 18–22 | 22–28 | 27–33 | 32–38 | 37–43 |
There is some debate over whether a polyp detection rate (PDR) or polypectomy rate can be used reliably as a surrogate for ADR. The benefit would be ease of calculation by avoiding linking with pathology results facilitating tracking given the logistical hurdles when using a registry to determine ADR. PDR is highly correlated with ADR, with proposed benchmarks of 40% in men and 30% in women. If there is concern over gaming the system, in which endoscopists report and/or remove polyps of which few are adenomas, sporadic audits with pathology reports could help prevent this. In the Clinical Outcomes Research Initiative registry, the use of polyps greater than 9 mm as a surrogate for advanced neoplasia is 84% specific, suggesting that surrogate markers might facilitate calculation of metrics within registries. In addition, novel algorithms may help facilitate linking pathology with endoscopy reports, especially in the setting of electronic health records.
Robust data support that ADR is a valid predictor of CRC. In a large study of more than 45,000 patients in a national CRC screening program in Poland, ADR and patient age were the only predictors of interval CRC, defined as CRC before the next surveillance examination was due (<5 years). Patient sex, doctor specialty, and cecal intubation rates were not associated with interval cancer. This study highlighted that measurement of ADR should have a role in continuous quality improvement programs for CRC screening. Some hypothesize that ADR may be a proxy for a more thorough examination of the colon. In a large German study, ADR was associated with endoscopist continuing medical education attendance and colonoscope instrument model, but not endoscopist procedural volume or withdrawal times.
Numerous studies have attempted to address whether or not ADR can be improved. A systematic review that included 7 studies and 10 abstracts found that improving ADR is difficult. This is exemplified by a study of 5 ambulatory endoscopy centers in Minnesota in which they attempted to systematically evaluate variability in ADR over time after application of specific quality improvement programs. None of the interventions (blinded and unblinded review of individual ADR, education about colonoscopy quality literature highlighting ADR goals and importance of withdrawal time, discussion between practice leaders and poor performing endoscopists, and financial consequences for withdrawal time <6 minutes) resulted in a significant improvement in ADR, which was associated only with patient factors (age, sex, and bowel prep quality). More research needs to be conducted to determine methods for improving ADR among low performers.
In addition, although ADR is typically calculated from traditional adenomas, the importance of serrated lesions is apparent. Whether serrated lesions should be included in the measurement of ADR or whether they merit their own metric remains to be determined.
Cecal Intubation Rates
Complete colonoscopy to the cecum is necessary for detection of a substantial fraction of proximal colon lesions. Quality indicators encourage documentation of cecal intubation with naming of the identified cecal landmarks (appendiceal orifice and ileocecal valve) and photographs. Intubation of the cecum should be achieved in greater than or equal to 95% of healthy subjects and greater than or equal to 90% of all colonoscopies. Cecal intubation rates are associated with postcolonoscopy CRC. In a large database study from Canada, higher cecal intubation rates were associated with protection from CRC in the right side. In a study in the UK, higher cecal intubation rates were similarly associated with higher ADRs.
Withdrawal Times
Withdrawal time, defined as the time from the colonoscope reaching the cecum to removal of the instrument from the patient, is considered a quality indicator in colonoscopy. Expert opinion suggests that the mean withdrawal time should be greater than or equal to 6 minutes in colonoscopies with normal results performed in patients with intact colons. This recommendation was qualified by the statement that, for those with adequate ADR, secondary measures such as withdrawal time are of less importance. Withdrawal time should not be applied to individual patient cases but must be averaged over many cases for an individual endoscopist.
The importance of withdrawal time and establishment of a threshold of 6 minutes came after publication of a study of 12 gastroenterologists in a community-based practice. The investigators compared the differences in ADR between endoscopists with greater than or equal to 6 minutes and less than 6 minutes withdrawal times. They found a strong correlation between mean withdrawal time on cases without polypectomy and detection of lesions (Spearman rank correlation coefficient [r s ] = 0.90, P <.001). Endoscopists with mean withdrawal time greater than or equal to 6 minutes also detected more advanced lesions (6.4% vs 2.3%, P = .005).
However, adopting a minimum withdrawal time alone is not likely to result in a substantially improved ADR. Simply recording withdrawal time did not improve ADR in one study. After the institution of using a cecal time stamp to record withdrawal time, PDR did not change significantly. Another study in Peru found that adopting a 6-minute or longer withdrawal time minimum did not change PDR. This study should be interpreted with caution because of overall low rates of PDR, in the range of 15% to 16%. Confidential feedback on withdrawal time with follow-up monitoring resulted in an increase in withdrawal time and in PDR, but not ADR. Mean withdrawal time without polyps went from 6.6 minutes to 8.1 minutes ( P <.0001), PDR went from 33% to 38% ( P = .04), without a significant change in ADR (20%–23%, P = .17). In a study of 42 endoscopists at an academic medical center, an institution-wide policy requiring a minimum of 7 minutes withdrawal time per case increased the proportion of examinations with mean withdrawal time of 7 minutes (65%–100%), but did not affect PDR. In addition, a study of a large German colonoscopy registry found that withdrawal time was not associated with ADR.
Withdrawal time is a surrogate marker for ADR and thus has limited value if endoscopists are already performing careful inspections. However, for those with low ADR, withdrawal time should be measured to see if short inspection time might be a modifiable factor for improvement.
Bowel Preparation Quality
The diagnostic accuracy of colonoscopy depends on the cleanliness of the colon and ability to visualize lesions. Poor preparation leads not only to missed lesions but also prolonged duration of procedure, repeated examinations at earlier intervals, increased complications, and excessive costs. The quality of bowel preparation should be documented in every procedure note. Qualitative descriptives (excellent, good, fair, poor) used in clinical practice lack standardized definitions and the Quality Assurance Task Force and Multi-Society Task Force on CRC advocate the use of “Inadequate to exclude polyps >5 mm in size” as a cutoff for repeating colonoscopy. The Ottawa and Aronchick bowel preparation rating scales were created as potential standardized bowel preparation scales, but were limited by lack of extensive validation and reliability testing. Furthermore, the Ottawa scale is complex, limiting practical use, and the Aronchick scale relies on global assessments that do not address individual colonic segments. The Boston Bowel Preparation Scale has been shown to be reliable and was validated prospectively, showing correlation with important outcomes like polyp detection, and has been incorporated in the Clinical Outcomes Research Initiative (CORI) and ProVation endowriters. However, there are no rating scales that receive universal acceptance as a gold standard.
If bowel preparation is inadequate in more than 10% of examinations, this may reflect quality-control issues and special attention may need to be given to patient education and type of preparation. Bowel preparation considerations are covered by Sharara and colleagues in more detail elsewhere in this issue.
Complications
Of the known complications of colonoscopy, only the incidences of perforation and postpolypectomy bleeding are proposed as quality measures. A benchmark has been set such that, if perforation rates are greater than 1 in 500 for all colonoscopies or 1 in 1000 for screening colonoscopies, evaluation should be pursued. Bleeding rates greater than 1% should prompt evaluation of whether inappropriate practices are taking place. Some data suggest that perforation rates may be higher among low-volume endoscopists. In an administrative database study of more than 97,000 patients undergoing outpatient colonoscopy in Canada, older age, male sex, having a polypectomy, and having the colonoscopy performed by a low-volume endoscopist (<300/y) were associated with increased odds of bleeding or perforation.
The performance benchmarks established by the Joint American Society of Gastrointestinal Endoscopy/American College of Gastroenterology Task Force on Quality Indicators for Colonoscopy were based on available literature; however, without proper documentation or systems for capturing delayed complications, rates may be under-reported, rendering the rate of acceptable complications inaccurate. A structured assessment tool was used to survey patients who had undergone colonoscopy in the Netherlands to determine major adverse events (hospital visit required), minor adverse events, and days missed from work. Adverse events were further categorized as definite, possible, or unrelated adverse events. The rate of definite major and minor events was 1% and 29% respsectively. Development of a proper lexicon for reporting complications should also help promote the consistent and accurate classification of adverse events.
Colonoscopy-related complications are covered in detail elsewhere in this issue.
Documentation
Although proper documentation may not at seem to affect patient outcomes related to colonoscopy, it plays an essential role in the ability to track indicators and develop benchmarks for performance. The absence of key information hinders communication with other physicians and may impede appropriate follow-up, whether too soon or delayed.
In the past, there has been variability in the quality of colonoscopy reports and documentation. A study of colonoscopy reports as part of a statewide screening program in Maryland analyzed 25 data elements and found that 27% of reports did not document bowel preparation quality, 18% did not use specific cecal landmarks, and, in cases with polyps, size and morphology were missing 13% and 47% of the time, respectively. A different study of 4800 colonoscopies by 116 Dutch endoscopists also found considerable variability in documentation of the quality of bowel prep and cecal landmarks. A study of 135 reports from the US community setting also showed low completeness rates.
Even with the use of a computer-generated standardized endoscopy report within the CORI network, 13.9% did not include bowel preparation quality, and cecal landmarks were not recorded in 14%. In addition, 10% did not include comorbidity classification, and key polyp descriptors were often missing.
This variability in reporting led to the development of the standardized Colonoscopy Reporting and Data System (CO-RADS) in 2007. CO-RADS suggests key areas for documentation ( Box 1 ). The literature suggests that colonoscopy reporting has improved since CO-RADS, whether because of the publication or temporal trends. A quality audit of 250 colonoscopy reports in 2009 showed improvement in quality of reporting, with 100% listing indication and informed consent, 99.6% prep quality, 78.8% cecal landmarks, 67% photographic documentation of the cecum, and 65.8% and 62.2% polyp size and morphology, respectively. Targeted modifications to electronic colonoscopic reporting systems can improve the quality of reports. Changes to software such as drop-down menus and visual cues to optimize completion of required fields have helped improve reporting.
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