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Increase in VA Drug Co-Payment Resulted in Decrease in Veterans' Adherence to Some Medications


  • A medication co-payment increase from $2 to $7 adversely impacted adherence to statins and anti-hypertensives by Veterans subject to the co-payment, but the impact was greatest among Veterans taking oral hypoglycemic medication. Adherence to all medications increased in the short term for all Veterans (12 months after co-payment increase), but then declined in the longer term (subsequent 11-month period). Authors suggest that the initial increase may have been due to physicians encouraging their patients to stockpile medications in anticipation of the co-payment increase.
  • The impact of the co-payment increase was particularly adverse for Veterans with diabetes who were responsible for co-payments. Their adherence to oral hypoglycemic medication in the period 13-23 months after the co-payment increase was 10.3% lower than their pre-period adherence - and 9% lower than comparable Veterans who were exempt from co-payments.

Between 2000 and 2005, average medication co-payments for commercially insured individuals increased, and cost-related medication non-adherence increased along with the higher co-payments. VA's co-payment policy mirrored these market trends by increasing medication co-payments from $2 to $7 for a 30-day fill in February 2002. This study examined the impact of the VA medication co-payment increase on adherence to diabetes, hypertension, and hyperlipidemic medications by Veterans with diabetes or hypertension at 4 VAMCs during a 35-month period (2/01--12/03). Using VA data, investigators compared medication adherence for Veterans who were exempt from co-payments with Veterans who were not exempt, including: 1069 exempt and 1069 non-exempt Veterans with diabetes, 3545 exempt and 3545 non-exempt Veterans with hypertension, and 2029 exempt and 2029 non-exempt Veterans who were prescribed statins. The main outcome measured was adherence to medication at 12 months before and 23 months after the co-payment increase. Exemption from medication co-payment is based upon a Veteran's priority group status.


  • Veterans' use of non-VA medications was not assessed, thus it is possible that Veterans were obtaining needed medications via Medicaid or private insurance.


  • Since this study, VA has increased medication co-payments to $8. The authors suggest that co-payment increases be carefully considered to ensure that Veterans who have greater comorbidity and lower incomes than the general U.S. population do not forgo needed medications.

AUTHOR/FUNDING INFORMATION: This study was funded through HSR&D. Dr. Maciejewski is part of HSR&D's Center for Health Services Research in Primary Care located in Durham, NC.

PubMed Logo Maciejewski M, Bryson C, Perkins M, et al. Increasing Co-Payments and Adherence to Diabetes, Hypertension and Hyperlipidemic Medications. American Journal of Medicine January 2010;16(1):

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HSR&D requires notification by HSR&D-funded investigators about all articles accepted for publication. These journal articles are reviewed by HSR&D and publication briefs or summaries are written for a select number of articles that are then forwarded to VHA Central Office leadership to keep them informed about important findings or information. Articles to be summarized are selected by HSR&D based on timeliness of the findings, interest of leadership, or potential impact on the organization. Publication briefs are written for only a small number of HSR&D published articles. Visit the HSR&D citations database for a complete listing of HSR&D articles and presentations.