Enrollment in Integrated Special Needs Plans Among Dually Eligible Beneficiaries With Serious Mental Illness.

Abstract

Fragmentation between Medicare and Medicaid exacerbates access barriers, delays in care, and poor financial and health outcomes among the more than 4 million dually eligible beneficiaries with serious mental illness (SMI). Integrated dual-eligible special needs plans (D-SNPs), including highly integrated D-SNPs (HIDE-SNPs) and fully integrated D-SNPs (FIDE-SNPs), are Medicare Advantage (MA) plans that financially integrate Medicare and Medicaid benefits and may address the significant behavioral health, medical, and long-term service and support needs in this population. To examine enrollment and disenrollment in integrated D-SNPs relative to other Medicare options among dually eligible beneficiaries with SMI from 2019 to 2022. This retrospective cohort study of a 20% sample of dually eligible beneficiaries with SMI and full Medicaid benefits used Medicare administrative data from 2019 to 2022, including traditional Medicare fee-for-service claims data and MA encounter data. Data were analyzed from September 1, 2025, to April 3, 2026. Enrollment and disenrollment in integrated D-SNPs relative to other Medicare options (traditional Medicare, standard MA, and coordination-only D-SNPs) from 2019 to 2022, as well as enrollee demographic, clinical, and geographic characteristics. This study included 719 542 dually eligible beneficiaries with a diagnosis of SMI (mean [SD] age, 64 [16] years; 459 555 women [63.9%]). The proportion of dually eligible beneficiaries with SMI enrolled in integrated HIDE-SNPs or FIDE-SNPs increased from 2.4% in 2019 to 17.2% in 2022, with a corresponding decrease in traditional Medicare enrollment from 58.6% to 42.6% in the same period. Cardiovascular disease (CVD), which is associated with excess mortality in SMI, was prevalent: 32.1% of beneficiaries had 3 CVD risk factors. More than half of states had no integrated D-SNP offerings, including states ranked highest for prevalence of comorbid CVD among dually eligible beneficiaries with SMI. A total of 10.3% of dually eligible beneficiaries with SMI enrolled in HIDE-SNPs and 6.1% of beneficiaries enrolled in FIDE-SNPs in 2021 disenrolled by 2022, relative to 20.9% disenrollment from standard MA. This retrospective cohort study of dually eligible beneficiaries with SMI found increases in integrated D-SNP enrollment and limited disenrollment, which may suggest a high level of enrollee satisfaction. More research is needed to assess the association of integrated D-SNP enrollment with health outcomes among dually eligible beneficiaries with SMI.