Medicaid prescription drug access restrictions: exploring the effect on patient persistence with hypertension medications

To compare rates of discontinuation of prescription therapy for hypertension in Medicaid patients with and without medication access restrictions. Retrospective cohort study. Prescription data were extracted from a pharmacy claims database in a large state that implemented a Medicaid preferred drug list (PDL), both before and after the PDL was implemented. Prescriptions filled between June 2000 and May 2003 were included. Medicaid patients taking prescription medications commonly used to treat hypertension were 39% (odds ratio = 1.39; 95% confidence interval, 1.21, 1.6) more likely to discontinue hypertension therapy after the restriction was implemented compared with Medicaid patients 1 year earlier when there were no restrictions. Patients were classified as "discontinued" if they had therapy available less than 50% of the time during the 12 months after implementation of the PDL. Before the PDL, 17% of patients receiving treatment with hypertension medication discontinued therapy. After the PDL, 21% of Medicaid patients taking hypertension medication discontinued therapy. After the PDL, Medicaid patients were significantly more likely to switch medications from a restricted to an unrestricted drug. Those patients also were less likely to have a restricted drug added to their therapy regimen. After implementation of the PDL, Medicaid patients were more likely to discontinue filling prescriptions for antihypertensive medication. Because hypertension management is an important challenge within the Medicaid community, the potential connection between access restrictions and patient adherence to medication therapy is a worthy topic for further exploratory studies and quantitative outcomes research.