Self-report of diabetes and claims-based identification of diabetes among Medicare beneficiaries.

OBJECTIVE This report compares self-reported diabetes in the National Health Interview Survey (NHIS) with diabetes identified using the Medicare Chronic Condition (CC) Summary file. BACKGROUND NHIS records have been linked with Medicare data from the Centers for Medicare & Medicaid Services. The CC Summary file, one of several linked files derived from Medicare claims data, contains indicators for chronic conditions based on an established algorithm. METHODS This analysis was limited to 2005 NHIS participants aged 65 and over whose records were linked to 2005 Medicare data. Linked NHIS participants had at least 1 month of fee-for-service Medicare coverage in 2005. Concordance between self-reported diabetes and the CC Summary indicator for diabetes is compared and described by demographics, socioeconomic status, health status indicators, and geographic characteristics. RESULTS Of the Medicare beneficiaries in the 2005 NHIS, 20.0% self-reported diabetes and 27.8% had an indicator for diabetes in the CC Summary file. Of those who self-reported diabetes in NHIS, the percentage with a CC Summary indicator for diabetes was high (93.1%). Of those with a CC Summary indicator for diabetes, the percentage self-reporting diabetes was comparatively lower (67.0%). Statistically significant differences by subgroup existed in the percentage concordance between the two sources. Of those with self-reported diabetes, the percentage with a CC Summary indicator differed by sex and age. Of those with a CC Summary indicator for diabetes, the percentage with self-reported diabetes differed by age, self-rated health, number of self-reported conditions, and geographic location. CONCLUSIONS Among Medicare beneficiaries who self-reported diabetes in NHIS, a high concordance was observed with identification of diabetes in the CC Summary file. However, among Medicare beneficiaries with an indicator for diabetes in the CC Summary file, concordance with self-reported diabetes in NHIS is comparatively lower. Differences exist by subgroup.