Download Free Electronic Document

FormatFile SizeNotes
PDF file 0.1 MB

Use Adobe Acrobat Reader version 10 or higher for the best experience.

Research Brief

To stem increases in prescription drug spending, pharmacy benefit managers and health plans are changing prescription drug benefits to steer patients toward less-expensive drugs or to require patients to assume a share of the costs. A systematic review of published studies analyzed how the salient cost-sharing features of prescription drug benefits may affect access to prescription drugs and synthesized what is known about how these features may affect medical spending and health outcomes. The following are key findings from the review:

  • Increased cost sharing is associated with lower rates of prescription drug treatment, worse adherence among existing users, and more frequent discontinuation of therapy. For each 10 percent increase in cost sharing, prescription drug use decreases by 2 percent to 6 percent, depending on the class of drug and the condition of the patient. Benefit caps, prior authorization requirements, and formulary restrictions also decrease prescription drug use.
  • For some chronic conditions—such as congestive heart failure, lipid disorders, diabetes, and schizophrenia—increased cost sharing is clearly associated with increased use of other health care services, offsetting any potential cost savings.
  • Low-income groups may be more sensitive than others to increased cost-sharing demands, but there is little evidence to support this claim, because studies conducted to date have not had access to information on patients' socioeconomic status.
  • The 2006 launch of Medicare Part D presents an opportunity to assess how a yearly benefit cap affects adherence to drug therapy.
  • Pharmacy benefit design is an important public health tool for improving population health, but the long-term health consequences of benefit changes are still uncertain.

This report is part of the RAND Corporation Research brief series. RAND research briefs present policy-oriented summaries of individual published, peer-reviewed documents or of a body of published work.

This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited; linking directly to this product page is encouraged. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial purposes. For information on reprint and reuse permissions, please visit

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.