Association of Medicare Part D Medication Out-of-Pocket Costs with Utilization of Statin Medications
Article first published online: 26 DEC 2012
© Health Research and Educational Trust
Health Services Research
Volume 48, Issue 4, pages 1311–1333, August 2013
How to Cite
Karaca-Mandic, P., Swenson, T., Abraham, J. M. and Kane, R. L. (2013), Association of Medicare Part D Medication Out-of-Pocket Costs with Utilization of Statin Medications. Health Services Research, 48: 1311–1333. doi: 10.1111/1475-6773.12022
- Issue published online: 4 JUL 2013
- Article first published online: 26 DEC 2012
- University of Minnesota Academic Health Center
- Medicare part D
To examine the association between statin out-of-pocket (OOP) costs and utilization among the Medicare Part D population.
Data Sources/Study Setting
2006–2008 administrative claims and enrollment data for the 5 percent Medicare sample.
Sample included 346,583 beneficiary-year observations of statin users enrolled in stand-alone prescription drug plans, excluding low-income subsidy recipients. We estimated the association between a plan's OOP statin costs and statin utilization using an instrumental variable approach to account for potential bias due to plan selection. Adherence was defined as percentage of days covered (PDC) of at least 80 percent. Plan OOP costs were constructed for a representative market basket of statin medications. Analyses controlled for demographic characteristics, cardiovascular disease risk, co-morbidity presence, and regional characteristics.
About 67 percent of the sample had a PDC of at least 80 percent. An increase in annual statin OOP from $200 (50th percentile) to $240 (75th percentile) was associated with a reduction in the rate of adherent beneficiaries from 67 percent to 56 percent (p < .001).
Greater OOP costs for statins are associated with reductions in statin utilization.