Transition to Medicare pharmacy coverage has uneven results for persons with mental illness

Medicaid coverage of prescription drugs varies widely across the country and includes states with strict caps on benefits and states with no such caps. The introduction of Medicare Part D benefits in 2006 created an equal benefit for Medicare enrollees, including those dually eligible for Medicare and Medicaid, but the overall he impact on persons with schizophrenia and bipolar disorder differed in states with strict caps and states with no caps. In a time-series analysis of continuously enrolled patient cohorts (2004-2007), we estimated changes in medication use before and after transitioning to Part D, comparing states that capped monthly prescription fills with states with no prescription limits. We used Medicaid and Medicare claims from a 5% national sample of community-dwelling, nonelderly disabled dual enrollees with schizophrenia (n = 5554) or bipolar disorder (n = 3675). After the transition to Part D, the prevalence of untreated illness among patients with a bipolar disorder decreased 17.2% in states with strict caps and remained the same in states with no caps; however, for patients with schizophrenia, the prevalence of untreated illness increased by 23.3% in no-cap states while the rate stayed the same in states with strict caps. Overall medication use increased substantially after Part D in strict-cap states: prescription fills were 35.5% higher among patients with a bipolar disorder and 17.7% higher than predicted among schizophrenic patients; overall use in no-cap states was unchanged in both cohorts. The effects of transitioning from Medicaid to Medicare Part D on essential treatment of serious mental illness vary by state. Transition to Part D in states with strict drug benefit limits may reduce rates of untreated illness among patients with bipolar disorders, who have high levels of overall medication use. Access to antipsychotic treatment may decrease after Part D for patients with a serious mental illness living in states with relatively generous uncapped Medicaid coverage.

Citation:
Changes in drug coverage generosity and untreated serious mental illness: transitioning from Medicaid to Medicare Part D. Madden JM, Adams AS, LeCates RF, Ross-Degnan D, Zhang F, Huskamp HA, Gilden DM, Soumerai SB. JAMA Psychiatry. 2015 Feb;72(2):179-88.



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