Matching colonoscopy and pathology data in population-based registries: Development of a novel algorithm and the initial experience of the New Hampshire Colonoscopy Registry

Background: The quality of polyp-level data in a population-based registry depends on the ability to match each polypectomy recorded by the endoscopist to a specific diagnosis on the pathology report. Objective: To review impediments encountered in matching colonoscopy and pathology data in a population-based registry. Design: New Hampshire Colonoscopy Registry data from August 2006 to November 2008 were analyzed for prevalence of missing reports, discrepancies between colonoscopy and pathology reports, and the proportion of polyps that could not be matched because of multiple polyps submitted in the same container. Setting: New Hampshire Colonoscopy Registry. Patients: This study involved all consenting patients during the study period. Intervention: Develop an algorithm for capturing number, size, location, and histology of polyps and for defining and flagging discrepancies to ensure data quality. Main Outcome Measurements: The proportion of polyps with no assumption or discrepancy, the proportion of patient records eligible for determining the adenoma detection rate (ADR), and the number of patients with <3 adenomas. Results: Only 50% of polyps removed during this period were perfectly matched, with no assumption or discrepancy. Records from only 69.9% and 29.7% of eligible patients could be used to determine the ADR and the number of patients with <3 adenomas, respectively. Limitations: Rates of missing reports may have been higher in the early phase of establishment of the registry. Conclusion: This study highlights the impediments in collecting polyp-level data in a population-based registry and provides useful parameters for evaluating the quality and accuracy of data obtained from such registries.