National and state trends in enrollment and spending for dual eligibles under age 65 in Medicaid managed care

Abstract Background To reduce costs and improve care, states are increasingly enrolling individuals with disabilities in Medicaid managed care. Many states allow or require adults who are dually eligible for Medicaid and Medicare to enroll in these plans. Objective This study (1) quantifies changes in enrollment by managed care arrangement for duals under age 65, between 2005 and 2008 and (2) compares enrollment and spending between dual eligibles and Medicaid-only beneficiaries. Methods We used Medicaid Analytic eXtract data to compare the Medicaid enrollment and spending for all-year, full-benefit dual eligibles ages 21–64 with that of Medicaid-only Supplemental Security Income (SSI) and disabled beneficiaries. The study population was classified into 9 types of managed care to quantify enrollment and calculate expenditures by year. Results Nationwide, the proportion of adult duals in managed care increased from 2005 to 2008, with the expansion of prepaid health plans (PHPs) (31.0%–46.6%), particularly behavioral health PHPs, driving the increase. In 2008, Medicaid-only disabled adults were three times as likely as dual adults to enroll in comprehensive managed care (CMC) (35.1% versus 11.7%). Average Medicaid expenditures per enrollee differed markedly by managed care arrangement and state. Conclusions From 2005 to 2008, there was little expansion of CMC among adult duals, while the use of PHPs to cover carved out services increased greatly. New federal initiatives aim to reduce barriers to enrolling duals into comprehensive, integrated managed care. With expanded enrollment, it will be important to monitor enrollment and evaluate whether integration improves care.