The Impact of Prescription Drug Coverage on Disparities in Adherence and Medication Use: A Systematic Review

Cameron M. Kaplan, Teresa M. Waters, Emily R. Clear, Elizabeth E. Graves, Stephanie Henderson

Research output: Contribution to journalReview articlepeer-review


Prescription drug cost-sharing is a barrier to medication adherence, particularly for low-income and minority populations. In this systematic review, we examined the impact of prescription drug cost-sharing and policies to reduce cost-sharing on racial/ethnic and income disparities in medication utilization. We screened 2,145 titles and abstracts and identified 19 peer-reviewed papers that examined the interaction between cost-sharing and racial/ethnic and income disparities in medication adherence or utilization. We found weak but inconsistent evidence that lower cost-sharing is associated with reduced disparities in adherence and utilization, but studies consistently found that significant disparities remained even after adjusting for differences in cost-sharing across individuals. Study designs varied in their ability to measure the causal effect of policy or cost-sharing changes on disparities, and a wide range of policies were examined across studies. Further research is needed to identify the types of policies that are best suited to reduce disparities in medication adherence.

Original languageEnglish
Pages (from-to)87-95
Number of pages9
JournalMedical Care Research and Review
Issue number2
StateAccepted/In press - 2023

Bibliographical note

Funding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This publication was made possible by Grant Number (R01AG054424) from the National Institute on Aging at the National Institutes of Health (NIH).

Publisher Copyright:
© The Author(s) 2023.


  • cost sharing
  • disparities
  • health insurance
  • medication adherence
  • prescription drugs

ASJC Scopus subject areas

  • Health Policy


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