Race/Ethnicity and economic differences in cost-related medication underuse among insured adults with diabetes. The TRIAD study.

doi:10.2337/dc07-1341

Race/Ethnicity and economic differences in cost-related medication underuse among insured adults with diabetes. The TRIAD study.

Chien-Wen Tseng, MD, MPH (cwtseng{at}hawaii.edu)^1,,²,
Ed Tierney, MPH³,
Robert B Gerzoff, MS³,
R Adams Dudley, MD, MBA⁴,
Beth Waitzfelder, PhD¹,
Ronald T Ackermann, MD, MPH⁵,
Andrew J Karter, PhD⁶,
John Piette, PhD⁷,
Jesse Crosson, PhD⁸,
Quyen Ngo-Metzger, MD, MPH⁹,
Richard Chung, MD¹⁰ and
Carol M Mangione, MD, MSPH¹¹

¹ Pacific Health Research Institute, Honolulu, HI
² Department of Family Medicine and Community Health, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI
³Division of Diabetes Translation, Centers for Disease Control and Prevention, Atlanta, GA
⁴Department of Medicine and Institute for Health Policy Studies, University of California, San Francisco, San Francisco, CA
⁵Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
⁶Division of Research, Kaiser Permanente Medical Care Program, N. California, Oakland, CA
⁷Department of Veterans Affairs Center for Practice Management and Outcomes Research and Department of Internal Medicine, University of Michigan, Ann Arbor, MI
⁸Department of Family Medicine, University of Medicine and Dentistry, New Jersey, New Jersey Medical School, Newark, NJ
⁹Division of General Medicine and Primary Care and the Center for Health Policy Research, University of California Irvine College of Medicine, Irvine, CA
¹⁰Hawaii Medical Services Association, Honolulu HI
¹¹David Geffen School of Medicine and School of Public Health, University of California, Los Angeles, Los Angeles, CA

Abstract

Objective: To examine racial/ethnic and economic variation in cost-related medication underuse among insured adults with diabetes.

Research Design and Methods: We surveyed 5086 participants from the multi-center Translating Research Into Action for Diabetes (TRIAD) study. Respondents reported whether they used less medication because of cost in the past 12 months. We examined unadjusted and adjusted rates of cost-related medication underuse, using hierarchical regression, to determine if race/ethnicity differences still existed after accounting for economic, health, and other demographic variables.

Results: Participants were 48% white, 14% African-American, 14% Latino, 15% Asian/Pacific Islander, and 8% other. Overall, 14% reported cost-related medication underuse. Unadjusted rates were highest for Latinos (23%) and African Americans (17%), compared to whites (13%), Asian/Pacific Islanders (11%), and others (15%). In multivariate analyses, race/ethnicity significantly predicted cost-related medication underuse (p=0.048). However adjusted rates were only slightly higher for Latinos (14%) than whites (10%) (p=0.026), and were not significantly different for African Americans (11%), Asian/Pacific Islanders (7%), and others (11%). Income and out-of-pocket drug costs showed the greatest differences in adjusted rates of cost-related medication underuse: 15% vs. 5% for participants with income <= $25K vs. >$50K, and 24% vs. 7% for participants with out-of-pocket costs > $150/month vs. <=$50/month.

Conclusions: One in seven participants reported cost-related medication underuse. Rates were highest among African Americans and Latinos, but were related to lower incomes and higher out-of-pocket drug costs in these groups. Interventions to decrease racial/ethnic disparities in cost-related medication underuse should focus on decreasing financial barriers to medications.