Data Sources for Measuring Colorectal Endoscopy Use Among Medicare Enrollees

Department of Medicine, University of North Carolina at Chapel Hill, North Carolina, United States
Cancer Epidemiology Biomarkers & Prevention (Impact Factor: 4.13). 11/2007; 16(10):2118-27. DOI: 10.1158/1055-9965.EPI-07-0123
Source: PubMed


Estimates of colorectal cancer test use vary widely by data source. Medicare claims offer one source for monitoring test use, but their utility has not been validated. We compared ascertainment of sigmoidoscopy and colonoscopy between three data sources: self reports, Medicare claims, and medical records.
The study population included Medicare enrollees residing in North Carolina (n = 561) who had participated in a telephone survey on colorectal cancer tests. Medicare claims were obtained for the 5 years preceding the survey (January 1, 1998 to December 31, 2002). Information about sigmoidoscopy and colonoscopy procedures conducted in physician offices were abstracted from medical records. Sensitivity, specificity, positive predictive value, negative predictive value, agreement, and kappa statistics were calculated using the medical record as the gold standard. Agreement on specific procedure type and purpose was also assessed.
Agreement between claim and medical record regarding whether an endoscopic procedure had been done was high (over 90%). Agreement between self report and medical record and between self report and claim was good (79% and 74%, respectively). All three data sources adequately distinguished the type of procedure done. None of the data sources showed reliable levels of agreement regarding procedure purpose (screening or diagnostic).
Medicare claims can provide accurate information on whether a patient has undergone colorectal endoscopy and may be more complete than physician medical records. Medicare claims cannot be used to distinguish screening from diagnostic tests. Recognizing this limitation, researchers who use Medicare claims to assess rates of colorectal testing should include both screening and diagnostic endoscopy procedures in their analyses.

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    • "The true indication for colonoscopy is the clinical rationale for the referral for testing, but this is difficult to measure from medical records or administrative data because the reasons for testing are not consistently documented [18]. Assigning an indication may also be difficult due to the multiplicity of reasons often recorded for a particular test or when common gastrointestinal symptoms, which have a low predictive value for CRC diagnosis, [19-21] are recorded at the time a colonoscopy is recommended or performed [15]. "
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    ABSTRACT: Accurate indication classification is critical for obtaining unbiased estimates of colonoscopy effectiveness and quality improvement efforts, but there is a dearth of published systematic classification approaches. The objective of this study was to evaluate the effects of data-source and adjudication on indication classification and on estimates of the effectiveness of screening colonoscopy on late-stage colorectal cancer diagnosis risk. This was an observational study in members of four U.S. health plans. Eligible persons (n = 1039) were age 55-85 and had been enrolled for 5 years or longer in their health plans during 2006-2008. Patients were selected based on late-stage colorectal cancer diagnosis in a case-control design; each case patient was matched to 1-2 controls by study site, age, sex, and health plan enrollment duration. Reasons for colonoscopies received in the 10-year period before the reference date were collected from three medical records sources (progress notes; referral notes; procedure reports) and categorized using an algorithm, with committee adjudication of some tests. We evaluated indication classification concordance before and after adjudication and used logistic regressions with the Wald Chi-square test to compare estimates of the effects of screening colonoscopy on late-stage colorectal cancer diagnosis risk for each of our data sources to the adjudicated indication. Classification agreement between each data-source and adjudication was 78.8-94.0% (weighted kappa = 0.53-0.72); the highest agreement (weighted kappa = 0.86-0.88) was when information from all data sources was considered together. The choice of data-source influenced the association between screening colonoscopy and late-stage colorectal cancer diagnosis; estimates based on progress notes were closest to those based on the adjudicated indication (% difference in regression coefficients = 2.4%, p-value = 0.98), as compared to estimates from only referral notes (% difference in coefficients = 34.9%, p-value = 0.12) or procedure reports (% difference in coefficients = 27.4%, p-value = 0.23). There was no single gold-standard source of information in medical records. The estimates of colonoscopy effectiveness from progress notes alone were the closest to estimates using adjudicated indications. Thus, the details in the medical records are necessary for accurate indication classification.
    Full-text · Article · Feb 2014 · BMC Cancer
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    • "Our study did not evaluate the accuracy of the endoscopy with respect to type of exam (colonoscopy vs. sigmoidoscopy) or reason for exam (screening vs. diagnosis), however, a few studies have done so. Not surprisingly, they have all found that administrative data are not adequate for assessing this level of specificity with respect to type or reason for exam [9,27-29]. For instance, Schenck et al. found Medicare claims to be accurate for identifying endoscopies but not for distinguishing screening from diagnostic tests. "
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    ABSTRACT: Background Validation of administrative data is important to assess potential sources of bias in outcome evaluation and to prevent dissemination of misleading or inaccurate information. The purpose of the study was to determine the completeness and accuracy of endoscopy data in several administrative data sources in the year prior to colorectal cancer diagnosis as part of a larger project focused on evaluating the quality of pre-diagnostic care. Methods Primary and secondary data sources for endoscopy were collected from the Alberta Cancer Registry, cancer medical charts and three different administrative data sources. 1672 randomly sampled patients diagnosed with invasive colorectal cancer in years 2000–2005 in Alberta, Canada were included. A retrospective validation study of administrative data for endoscopy in the year prior to colorectal cancer diagnosis was conducted. A gold standard dataset was created by combining all the datasets. Number and percent identified, agreement and percent unique to a given data source were calculated and compared across each dataset and to the gold standard with respect to identifying all patients who underwent endoscopy and all endoscopies received by those patients. Results The combined administrative data and physician billing data identified as high or higher percentage of patients who had one or more endoscopy (84% and 78%, respectively) and total endoscopy procedures (89% and 81%, respectively) than the chart review (78% for both). Conclusions Endoscopy data has a high level of completeness and accuracy in physician billing data alone. Combined with hospital in/outpatient data it is more complete than chart review alone.
    Full-text · Article · Oct 2012 · BMC Health Services Research
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