Linking Medicare-Medicaid Claims for Patient-Centered Outcomes Research Among Dual-Eligible Beneficiaries

BACKGROUND: Evaluation of Medicare-Medicaid integration models’ effects on patient-centered outcomes and costs requires multiple data sources and validated processes for linkage and reconciliation. OBJECTIVE: To describe the opportunities and limitations of linking state-specific Medicaid and Centers for Medicare & Medicaid Services administrative claims data to measure patient-centered outcomes for North Carolina dual-eligible beneficiaries. RESEARCH DESIGN: We developed systematic processes to (1) validate the beneficiary ID linkage using sex and date of birth in a beneficiary ID crosswalk, (2) verify dates of dual enrollment, and (3) reconcile Medicare-Medicaid claims data to support the development and use of patient-centered outcomes in linked data. PARTICIPANTS: North Carolina Medicaid beneficiaries with full Medicaid benefits and concurrent Medicare enrollment (FBDE) between 2014 and 2017. MEASURES: We identified need-based subgroups based on service use and eligibility program requirements. We calculated utilization and costs for Medicaid and Medicare, matched Medicaid claims to Medicare service categories where possible, and reported outcomes by the payer. Some services were covered only by Medicaid or Medicare, including Medicaid-only covered home and community-based services (HCBS). RESULTS: Of 498,030 potential dual enrollees, we verified the linkage and FBDE eligibility of 425,664 (85.5%) beneficiaries, including 281,174 adults enrolled in Medicaid and Medicare fee-for-service. The most common need-based subgroups were intensive behavioral health service users (26.2%) and HCBS users (10.8%) for adults under age 65, and HCBS users (20.6%) and nursing home residents (12.4%) for adults age 65 and over. Medicaid funded 42% and 49% of spending for adults under 65 and adults 65 and older, respectively. Adults under 65 had greater behavioral health service utilization but less skilled nursing facility, HCBS, and home health utilization compared with adults 65 and older. CONCLUSIONS: Linkage of Medicare-Medicaid data improves understanding of patient-centered outcomes among FBDE by combining Medicare-funded acute and ambulatory services with Medicaid-funded HCBS. Using linked Medicare-Medicaid data illustrates the diverse patient experience within FBDE beneficiaries, which is key to informing patient-centered outcomes, developing and evaluating integrated Medicare and Medicaid programs, and promoting health equity.