Changes in antipsychotic medication use after implementation of a Medicaid mental health carve-out in the US.

BACKGROUND: Many Medicaid programmes now offer behavioural healthcare through managed care organizations. Medicaid programmes are concerned about carve-outs because the use of non-included services may rise, limiting the efficiencies anticipated with the implementation of managed care. There also exist concerns that patients with serious mental illness may receive reduced care through managed care and consequently have poorer outcomes.
OBJECTIVE: This study examined prescription drug utilization among Medicaid recipients with the implementation of a mental health carve-out plan in Florida. In particular, this study examined short-run changes in the utilization of antipsychotic medications among individuals diagnosed with schizophrenia or episodic mood disorders with the implementation of Prepaid Mental Health Plans (PMHPs) in Florida Medicaid.
METHODS: This study used Medicaid data from 38 counties in Florida that implemented the PMHP programme in 2005 and 2006. The sample was limited to individuals aged≤64 years who were continuously enrolled in Medicaid. Individuals were required to have at least two diagnoses of schizophrenia, episodic mood disorders, delusional disorders or other nonorganic disorders (three-digit International Classification of Diseases, Ninth Revision [ICD-9] code of 295-298). Five different outcome measures were examined on a monthly basis for the 6 months pre- and post-PMHP implementation: penetration; adherence; Medicaid expenditures for antipsychotics; polypharmacy (multiple antipsychotic medications); and whether dosing was within guidelines. Generalized estimating equations were used to estimate associations between individual and insurance characteristics, and the outcome variables. The analyses were conducted using SAS procedure GENMOD. Empirical (robust) standard errors were calculated to account for repeated observations on the same individual.
RESULTS: There were 153,720 monthly observations for the 12,810 people in the sample. Seventy-four percent of the sample was aged between 21 and 54 years, while 65% were female, 30% White, 14% Black and 44% Hispanic. The large proportion of Hispanics stems from the introduction of the PMHP programme in Dade County (Miami). The results indicate the implementation of the PMHP was associated with increased penetration, but reduced adherence, polypharmacy and expenditures by the Medicaid agency. There was no change in the likelihood of prescriptions being written within recommended dosage ranges.
CONCLUSION: The introduction of the PMHP was associated with short-run changes in medication utilization among individuals with serious mental illness.