Agreement between administrative claims and the medical record in identifying patients with a diagnosis of hypertension

Objective: This study evaluated the accuracy of 2 administrative claims-based selection rules to identify patients with hypertension (HTN) using medical records as the gold standard. Research Design: The claims database consisted of inpatient, outpatient, pharmacy, and eligibility claims for members of a single insurance company from January 2000 through March 2003. Medical records were abstracted for 258 matched patient pairs selected by Rule A (at least 1 HTN-related International Classification of Diseases, 9th Revision [ICD-9] claim) and 138 pairs selected by Rule B (at least 1 HTN-related ICD-9 and at least I HTN prescription claim) from 31 provider sites. Sensitivity and specificity of the 2 selection rules were computed using medical chart review as the gold standard for a diagnosis of HTN. Subjects: Of patients selected by Rule A, chart review identified 281 patients with and 235 patients without HTN. Of patients selected by Rule B, chart review identified 172 patients with and 104 patients without HTN. Results: The sensitivity and specificity was 70.8% and 74.9% for Rule A and 76.2% and 93.3% for Rule B. The kappa score was 0.45 for Rule A and 0.65 for Rule B. Conclusion: To identify patients with HTN, a selection rule using both a diagnosis and prescription claim has greater sensitivity and specificity than a rule using a diagnosis claim only.