Using the Medicare Current Beneficiary Survey to conduct research on Medicare-eligible veterans

The Medicare Current Beneficiary Survey (MCBS) is a longitudinal, multipurpose panel survey of a nationally representative sample of Medicare beneficiaries sponsored by the Centers for Medicare and Medicaid Services (CMS). The MCBS serves as a comprehensive data source on self-reported health and socioeconomic status, health insurance, healthcare utilization and costs, and patient satisfaction. CMS uses Medicare claims data to validate self-reported Medicare Fee-For-Service (FFS) utilization. Because the Veterans Health Administration (VHA) does not bill for services, CMS imputes VHA costs. This article addresses the quality of the MCBS dataset for conducting research on Medicare-eligible veterans by addressing the sample's representativeness, quality of self-reported data, and accuracy of imputed VHA cost estimates. We compared demographic data from the 1992 and 2001 National Survey of Veterans (NSV) with the MCBS 1992 and 2001 Cost and Use files. We compared self-reported VHA utilization and CMS's imputed costs with VHA administrative datasets. The VHA's Pharmacy Benefits Management (PBM) database is available from fiscal year (FY) 1999 onward, and the VHA Health Economics Resource Center's (HERC) Average Cost datasets are available from FY1998 onward. While the samples were comparable in terms of age, sex, and race, the MCBS respondents were in better health, less likely to be married, and more likely to be widowed than NSV respondents. MCBS underreporting rates were higher for VHA than Medicare outpatient events. Underreporting and differences between CMS's and HERC's costing methodologies contributed to lower MCBS versus VHA administrative person- and event-level costs. Alternatively, average annual VHA prescription costs per capita were higher in the MCBS than in the PBM data. Differences in socioeconomic characteristics of the NSV and MCBS samples may be attributable to differences in sampling methodologies. Higher underreporting rates for VHA versus Medicare FFS outpatient events are likely due to systemic differences between the VHA and private healthcare sectors. While VHA formulary discounts may not be reflected in MCBS's VHA prescriptions costs, lower PBM prescriptions costs are also due to deficient indirect cost data. Since reliable VHA utilization and cost data existed in either FY1998 or FY1999 onward, study goals include estimating the relative share and/or cost of care provided by Medicare and the VHA. Researchers with access to VHA datasets should consider merging them into the MCBS and replacing self-reported utilization and CMS's imputed costs with VHA administrative data. This replacement would significantly improve the accuracy, quality, and usefulness of the MCBS dataset for policy research.