Accuracy of administrative claims data for polypectomy

Background:

The frequency of polypectomy is an important indicator of quality assurance for population-based colorectal cancer screening programs. Although administrative databases of physician claims provide population-level data on the performance of polypectomy, the accuracy of the procedure codes has not been examined. We determined the level of agreement between physician claims for polypectomy and documentation of the procedure in endoscopy reports.

Methods:

We conducted a retrospective cohort study involving patients aged 50–80 years who underwent colonoscopy at seven study sites in Montréal, Que., between January and March 2007. We obtained data on physician claims for polypectomy from the Régie de l’Assurance Maladie du Québec (RAMQ) database. We evaluated the accuracy of the RAMQ data against information in the endoscopy reports.

Results:

We collected data on 689 patients who underwent colonoscopy during the study period. The sensitivity of physician claims for polypectomy in the administrative database was 84.7% (95% confidence interval [CI] 78.6%–89.4%), the specificity was 99.0% (95% CI 97.5%–99.6%), concordance was 95.1% (95% CI 93.1%–96.5%), and the kappa value was 0.87 (95% CI 0.83–0.91).

Interpretation:

Despite providing a reasonably accurate estimate of the frequency of polypectomy, physician claims underestimated the number of procedures performed by more than 15%. Such differences could affect conclusions regarding quality assurance if used to evaluate population-based screening programs for colorectal cancer. Even when a high level of accuracy is anticipated, validating physician claims data from administrative databases is recommended.Population-based screening programs for colorectal cancer rely heavily on the performance of colonoscopy as either the initial examination or as the follow-up to a positive screening by virtual colonography, double-contrast barium enema or fecal occult blood testing. Colonoscopy is the only screening examination accepted at 10-year intervals among people at average risk without significant polyps found. It allows direct visualization of the entire colon and rectum and permits removal of adenomatous polyps, precursors of colorectal cancer. The frequency of polypectomy is an important indicator of quality assurance for colorectal cancer screening programs.In the province of Quebec, physicians are reimbursed for medical services by the Régie de l’Assurance Maladie du Québec (RAMQ), the government agency responsible for administering the provincial health insurance plan. Physicians receive additional remuneration for performing a polypectomy if they include the procedure code in their claim.Data from physician claims databases are commonly used in health services research,^1–7 even though the data are collected for administrative purposes and physician reimbursement. Procedure codes in physician claims databases are presumed to have a very high level of agreement with data in medical charts.⁸ A physician making a claim will need to submit the diagnostic code and, when applicable, the procedure code. Studies that rely on physician claims databases can be divided into those that examine the diagnostic codes entered and those that examine the procedure codes entered. Few studies have attempted to validate procedure codes, and often not as the primary study objective.^9–14We conducted a study to determine the level of agreement between physician claims for polypectomy and documentation of the procedure in endoscopy reports.