Medicaid Spending in Coordination-Only Dual-Eligible Special Needs Plans.

Importance: More than 4 million Medicare beneficiaries have enrolled in dual-eligible Special Needs Plans (D-SNPs), and coordination-only D-SNPs are common. Little is known about the impact of coordination-only D-SNPs on Medicaid-covered services and spending, including long-term services and supports, which are financed primarily by Medicaid. Objective: To evaluate changes in Medicaid fee-for-service (FFS) spending before and after new enrollment in coordination-only D-SNPs vs new enrollment in non-D-SNP Medicare Advantage (MA) plans among community-living beneficiaries enrolled in both Medicare and North Carolina Medicaid. Design, Setting, and Participants: This cohort study applied a new user, active comparator design to control for selection into MA and inverse probability of treatment weighting to improve the comparability between groups. The cohort included community-living dual-eligible Medicare and Medicaid beneficiaries in North Carolina with 365 days of Medicare FFS enrollment prior to new enrollment in D-SNP (treatment) or other MA plan (active comparator). Linked 100% Medicare and North Carolina Medicaid claims data (2014-2017) provided payments across both payers prior to MA enrollment; after MA enrollment, payments for Medicaid-funded services and supplemental Medicaid payments for Medicare-funded services were observed. Data were analyzed from August 2023 to November 2024. Exposure: New D-SNP enrollment. Main Outcomes and Measures: Outcomes included annualized 1-year Medicaid FFS spending overall and by claim type, including inpatient, outpatient, carrier, home health, personal care services, and behavioral health services. Results: Among 8869 participants in the D-SNP cohort, 4762 (53.7%) were younger than 65 years, 5833 (65.8%), were female, and 975 (11.0%) resided in rural areas. After inverse probability of treatment weighting, characteristics were similar among the comparison MA cohort of 4389 participants (4706 [53.2%] aged <65 years; 5739 [64.9%] female; 971 [11.0%] rural). There were no significant differences in Medicaid FFS spending per person-year (PPY) at baseline or differential change in the year following new enrollment (mean marginal effect, -$387 [95% CI, -$1274 to $501) between groups. There were significant differences between groups in the change in spending on long-term services and supports, with maintained spending on community-based personal care services following new enrollment in D-SNPs compared with reductions for other MA, resulting in a relative increase of $343 (95% CI, $147 to $539). Conclusions and Relevance: This cohort study found that coordination-only D-SNPs was associated with maintained North Carolina Medicaid FFS spending levels for long-term services and supports compared with other MA plans, despite limited integration requirements. However, to reduce or delay nursing home transitions, higher levels of integration may be necessary.