Changes in Care Associated With Integrating Medicare and Medicaid for Dual-Eligible Individuals.

Importance: There is growing interest in expanding integrated models, in which 1 insurer manages Medicare and Medicaid spending for dually eligible individuals. Fully integrated dual-eligible special needs plans (FIDE-SNPs) are one of the largest integrated models, but evidence about their performance is limited. Objective: To evaluate changes in care associated with integrating Medicare and Medicaid coverage in a FIDE-SNP in Pennsylvania. Design, Setting, and Participants: This cohort study using a difference-in-differences analysis compared changes in care between 2 cohorts of dual-eligible individuals: (1) an integration cohort composed of Medicare Dual Eligible Special Needs Plan enrollees who joined a companion Medicaid plan following a 2018 state reform mandating Medicaid managed care (leading to integration), and (2) a comparison cohort with nonintegrated coverage before and after the start of Medicaid managed care. Analyses were conducted between February 2022 and June 2023. Main Outcomes and Measures: Analyses examined outcomes in 4 domains: use of home- and community-based services (HCBS), care management and coordination, hospital stays and postacute care, and long-term nursing home stays. Results: The study included 7967 individuals in the integration cohort and 3832 individuals in the comparison cohort. In the integration cohort, the mean (SD) age at baseline was 63.3 (14.7) years, and 5268 individuals (66.1%) were female and 2699 (33.9%) were male. In the comparison cohort, the mean (SD) age at baseline was 64.8 (18.6) years, and 2341 individuals (61.1%) were female and 1491 (38.9%) were male. At baseline, integration cohort members received a mean (SD) of 2.83 (8.70) days of HCBS per month and 3.34 (3.56) medications for chronic conditions per month, and the proportion with a follow-up outpatient visit after a hospital stay was 0.47. From baseline through 3 years after integration, HCBS use increased differentially in the integration vs comparison cohorts by 0.61 days/person-month (95% CI, 0.28-0.94; P < .001). However, integration was not associated with changes in care management and coordination, including medication use for chronic conditions (-0.02 fills/person-month; 95% CI, -0.10 to 0.06; P = .65) or follow-up outpatient care after a hospital stay (-0.01 visits/hospital stay; 95% CI, -0.04 to 0.03; P = .61). Hospital stays did not change differentially between the cohorts. Unmeasured factors contributing to differential mortality limited the ability to identify changes in long-term nursing home stays associated with integration. Conclusions and Relevance: In this cohort study with a difference-in-differences analysis of 2 cohorts of individuals dually eligible for Medicare and Medicaid, integration was associated with greater HCBS use but not with other changes in care patterns. The findings highlight opportunities to strengthen how integrated programs manage care and a need to further evaluate their performance.