159726 Impact of Medicaid Preferred Drug Lists on Therapeutic Adherence

Tuesday, November 6, 2007: 3:30 PM

David B. Ridley, PhD , Fuqua School of Business, Duke University, Durham, NC
Kirsten Axelsen, MS , Economic and Policy Research, Pfizer, Inc., New York, NY
OBJECTIVES: Estimate rates of non-adherence for statins following implementation of a preferred drug list (PDL). METHODS: In a retrospective cohort study, a difference-in-difference-in-difference approach was used to estimate the impact of a PDL on statin utilization in an Alabama Medicaid population. The PDL restricted access to certain branded medications and imposed a monthly prescription limit. The use of restricted drugs was compared with unrestricted drugs in the months before and after the PDL in North Carolina (no restrictions) and Alabama. Pharmacy data from 2001 to 2005 were used to examine the effect of the Alabama PDL implemented in 2004. RESULTS: Following the PDL in Alabama, Medicaid beneficiaries treated with statins had an 82% higher relative odds of becoming non-adherent with statin therapy compared with North Carolina and with pre-PDL Alabama [odds ratio (OR) 1.82, 95% CI 1.57, 2.11]. Furthermore, patients taking a restricted statin were more likely to be non-adherent than unrestricted patients (OR 1.42, 95% CI 1.12, 1.80). In addition, among Medicaid beneficiaries taking a restricted statin, people aged 65 years or older were more likely to be non-adherent than their younger counterparts after the PDL (OR 1.33, 95% CI 1.02, 1.73). Fifty-one per cent of patients in the Alabama sample were non-adherent with statin therapy after the PDL, compared with 39% before. Non-adherence was 36% in North Carolina in both periods. CONCLUSION: Management of heart disease is an important challenge, especially for low-income patients. Policy makers should be aware that access restrictions can have adverse consequences on adherence.

Learning Objectives:
1) Learn about a way to examine the impact of medication therapy management programs on therapeutic adherence. 2) Describe how the effect of the policy on therapeutic adherence overall and on the elderly sub-population. 3) Consider therapeutic adherence, in addition to cost reduction, as an indicator of total effect of a medication utilization management program.

Keywords: Adherence, Medicare/Medicaid

Presenting author's disclosure statement:

Any relevant financial relationships? No
Any institutionally-contracted trials related to this submission?

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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