Health Economics, Policy and Law

Articles

Prescription drug co-payments and cost-related medication underuse

TODD H. WAGNERa1 c1, MICHELE HEISLERa2 and JOHN D. PIETTEa3

a1 Department of Veterans Affairs Health Economics Resource Center, Department of Health Research and Policy, Stanford University, USA

a2 Department of Veterans Affairs Center for Practice Management and Outcomes Research, Department of Internal Medicine, University of Michigan, Ann Arbor, USA

a3 Department of Veterans Affairs Center for Practice Management and Outcomes Research, Department of Internal Medicine, University of Michigan, Ann Arbor, USA

Abstract

Co-payments have been linked to the slowing growth in pharmaceutical spending over the last five years. However, patients with health problems frequently have difficulty affording their pharmacotherapy and fail to take their medication as prescribed. We examine the relationship between co-payment amounts and four types of cost-related underuse: taking fewer doses, postponing taking a medication, failing to fill a prescription at all, and taking medication less frequently than prescribed. We conducted a nationwide survey of US adults age 50 and over who take medication for a chronic condition. Participants provided information on 17 chronic conditions, medication they take for those conditions, and whether they underused any medication due to cost. We analyzed those who reported paying co-payments for their prescriptions (n = 2,869). Analysis involved multivariate logistic regression, with adjustments for survey weights and clustering. Our data show a strong positive association between co-payments and cost-related medication underuse. Although people differ in how they underuse medications, these behaviours are strongly associated with co-payment amount. Realigning the co-payments with cost-effectiveness data, also known as value-based insurance design, warrants further investigation.

Correspondence:

c1 Correspondence to: Todd H. Wagner, VA Palo Alto, 795 Willow Rd. (MPD-152), Menlo Park, CA 94025, USA. Email: twagner@stanford.edu

Footnotes

This study was funded by the Department of Veterans Affairs Health Services Research and Development Service. The views expressed in this article are those of the authors and do not necessarily represent the views of the Department of Veterans Affairs, Stanford University or the University of Michigan. John Piette is a VA Career Scientist. Michele Heisler is a VA Career Development Awardee. We appreciate helpful comments from two anonymous reviewers.