Impact of Medicaid Policy on Cardiovascular Drug Use and Clinical Outcomes

Principal Investigator: Michael A. Fischer, M.D., M.S.
Brigham and Women's Hospital

Purpose

This study evaluated the prevalence and effectiveness of different policy approaches used by State Medicaid programs to manage medication use, and the impact of these policies on outcomes, with a specific focus on cardiovascular medications. It covered two different sets of policies. The first set includes requiring prior authorization and use of preferred drug lists, typically for four major clinical classes of medications: lipid-lowering, antihypertensive, antiplatelet, and oral diabetes. The second set includes caps on the number of prescriptions covered and variations in required copayments, which generally cut across clinical classes of drugs.

Methods

The evaluation included analyses of both aggregate and patient-level claims data for virtually all State Medicaid programs, along with a review of information on program policies obtained from Web sites and published documents, and through direct contact with State Medicaid offices. Data on aggregate drug use came from publicly available files provided by the Centers for Medicare & Medicaid Services, including quarterly data on total prescriptions filled and amounts paid by individual agent. Patient-level data came from the Medicaid Analytic Extract file for calendar years 2001 through 2006. The authors developed interrupted time-series models to estimate the impact of specific policies on medication use and clinical outcomes.

Results

While prescription drug reimbursement policies varied widely across Medicaid programs, States increasingly adopted both sets of policies examined. In 2001 (the beginning of the study period), only a small percentage of States used prior authorization policies and preferred drug lists, but by the end of 2010 a majority used both policy approaches for at least some medications in each of the four clinical classes studied. Similarly, during this same period, an increasing number of States adopted policies placing a cap on the number of medications covered.

The evaluation found that while such restrictions were effective in reducing use of targeted medications, they could lead to adverse outcomes in terms of increased visits to emergency departments.

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