Spillover effects of restrictive drug formularies in the statin class: a descriptive study of the Medicaid preferred drug list in Texas
Wang, Y.R.
Managed Care Interface 19(11): 32-34
2006
ISSN/ISBN: 1096-5645 PMID: 17137239 Document Number: 600665
This study examines whether the implementation of Texas' Medicaid preferred drug list (PDL) influenced, or had a spillover effect, on the prescribing of statin products for non-Medicaid patients. Simvastatin and pravastatin were on the PDL, but atorvastatin was not. Physicians in Texas were categorized into four groups with increasing Medicaid exposure. Compared with physicians with very low, low, or medium Medicaid exposure, the non-Medicaid marketshare of atorvastatin dropped approximately two percentage points and the non-Medicaid marketshare of simvastatin and pravastatin increased by approximately one percentage point among physicians with high Medicaid exposure after six months. Therefore, the restrictive Medicaid PDL in Texas spilled over to non-Medicaid patients.