Using Claims Data for Epidemiologic Research

In this study, a method was developed to identify health plan members with hypertension from insurance claims, using medical records and a patient survey for validation. A sample of 2,079 patients from two study sites with medical service or pharmacy claims indicating a diagnosis of essential hypertension were surveyed, and the medical records of 182 of the 1,275 survey respondents were reviewed. Where the criteria to identify hypertensive patients used both the medical and pharmacy claims, there was 96% agreement with either the medical record or the patient survey. Where the criteria relied on medical claims alone, the agreement rate decreased to 74% with the medical record and 64% with the patient survey. Where the criteria relied on the pharmacy claims alone, the agreement rate was 67% with the medical record and 75% with the patient survey. Combined evidence from medical service and pharmacy claims yielded a high level of agreement with alternative, more costly sources of data in identifying patients with essential hypertension. As it is more thoroughly investigated, claims data should become a more widely accepted resource for epidemiologic research.