Increase in VA Prescription Co-Pay Leads to Decrease in Adherence to Statins for Veterans at Risk of Heart Disease
KEY FINDINGS:
- VA’s increase in drug co-payments from $2 to $7 adversely affected lipid-lowering medication adherence among Veterans, including those at high risk of coronary heart disease.
- After the increase in medication co-payments, the percent of Veterans who were adherent to lipid-lowering therapy declined significantly, with a decrease of 19.2% for Veterans paying all co-payments, 19.3% for Veterans with some co-payments, and 11.9% for Veterans with no co-payment. Regarding this finding, authors note that there may be changes over time common to all groups that happen because of external factors in the environment, e.g., changes in practice patterns, which may explain the decrease in adherence even for Veterans who have no drug co-payment.
- The co-payment increase was accompanied by a significant increase in the likelihood of having continuous gaps in lipid-lowering medication use. The odds of having a continuous gap of 90 days without medication use after co-payments increased compared to before the increase was nearly three times higher for Veterans paying all co-payments and twice as high for Veterans paying some co-payments.
BACKGROUND:
Statins, the most commonly used lipid-lowering agents, have been shown to significantly reduce the risk of future coronary events and cardiovascular mortality in patients at high risk for coronary disease.
In February 2002, VA increased drug co-payments from $2 to $7 per 30-day supply of each medication for many Veterans. Whether or not a veteran has a co-payment (and for which medications) depends on the veteran’s priority group (1-8), with some being exempt from all co-payments while others must pay for some or all medications. Investigators in this study analyzed VA administrative data and electronic medical records for 5,604 Veterans who received care at the Philadelphia VA Medical Center from 11/99 to 4/04, comparing changes in lipid-lowering medication use after the 2002 co-payment increase for Veterans exempt from all co-payment (n=495, priority group 1), versus those with a co-payment increase for some medications (n=2,793, priority groups 2-6) and Veterans who experienced an increase in co-payments for all medications (n=2,316, priority groups 7+8).
LIMITATIONS:
- Investigators only had access to VA prescription and medical data. Thus, the occurrence of medication gaps does not mean that Veterans did not fill prescriptions outside VA.
- The study did not evaluate whether the reduction in medication adherence had an adverse impact on cardiovascular outcomes or total medical expenditures.
AUTHOR/FUNDING INFORMATION:
This study was partly funded by HSR&D. Drs. Doshi and Volpp and Mr. Zhu are part of HSR&D’s Center for Health Equity Research and Promotion in Philadelphia, and Dr. Kimmel is a cardiologist at the Philadelphia VA Medical Center.
PUBLICATION DATE:
January 12, 2009 in Circulation (e-pub ahead of print)
Impact of a prescription copayment increase on lipid-lowering medication adherence in veterans. Doshi JA, Zhu J, Lee BY, Kimmel SE, Volpp KG. Circulation. 2009 Jan 27;119(3):390-7. Epub 2009 Jan 12.
