Venue: The Fuqua School of Business, Duke University, 1 Towerview Drive, Durham, NC 27708-0120

 

Presentation

Economic and Clinical Impacts of Prior Authorization for Antipsychotic and Anticonvulsant Medications among Medicaid Beneficiaries with Bipolar Disorder

Authors:

Presenter: Yuting Zhang (University of Pittsburgh)

Discussant: Douglas Leslie (Medical University of South Carolina)

Session: Understanding the Rapid Growth in Use and Explosion in Expenditures: What Factors Drive the Diffusion of Psychiatric Medications?

Room: Classroom C

When: Monday 8:30 a.m. - 10 a.m.

To control the rapid growth in prescription drug spending, both private and public insurance programs have increasingly relied on prior authorization (PA) policies, especially for new atypical antipsychotic (AA) and anticonvulsant (AC) medications. However, the effects of such policies on psychoactive medication use are unknown. This study examined the impact of a PA policy in Maine on AA/AC utilization, discontinuations in therapy, and drug expenditures among Medicaid beneficiaries with bipolar disorder.

We identified patients with bipolar disorder from Maine (study state) and New Hampshire (comparison state) using Medicaid and Medicare utilization data (2001-2004). We used an interrupted time-series and comparison group design to measure changes in AA/AC market share and expenditures among continuously enrolled patients (N=6,712). We used survival analysis to analyze the PA impact on treatment discontinuations and rates of switching medications among two newly treated cohorts before (7/02-2/03) and during the policy (7/03-2/04).

The PA policy reduced the prevalence of use of non-preferred AA and AC medications (those requiring PA) by 8 percentage points to 29% at the end of the 8-month policy period. The PA policy did not increase the prevalence of use of preferred agents (those not requiring PA). We found that the PA policy reduced total spending on bipolar medications by $27 per patient during the 8 month policy period. However, the hazard rate of treatment discontinuation for the policy cohort was 2.28 [95% CI: (1.36, 4.33)] higher than the pre-policy cohort, adjusting for secular trends in the comparison state.

The PA policy decreased non-preferred AA/AC use but also increased treatment discontinuations among individuals with bipolar disorder. The small reduction in pharmacy spending for bipolar treatment associated with the policy may have been due to higher rates of discontinuation rather than switching. Our findings indicate that the PA policy in Maine may increase patient risk without appreciable cost savings to the state.