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. 2011 Dec;46(6pt1):1963-85.
doi: 10.1111/j.1475-6773.2011.01286.x. Epub 2011 Jun 20.

Does medication adherence following a copayment increase differ by disease burden?

Virginia Wang  1 , Chuan-Fen Liu, Christopher L Bryson, Nancy D Sharp, Matthew L Maciejewski
Affiliations

Does medication adherence following a copayment increase differ by disease burden?

Virginia Wang et al. Health Serv Res. 2011 Dec.

Abstract

Objectives: To compare changes in medication adherence between patients with high- or low-comorbidity burden after a copayment increase.

Methods: We conducted a retrospective observational study at four Veterans Affairs (VA) medical centers by comparing veterans with hypertension or diabetes required to pay copayments with propensity score-matched veterans exempt from copayments. Disease cohorts were stratified by Diagnostic Cost Group risk score: low- (<1) and high-comorbidity (>1) burden. Medication adherence from February 2001 to December 2003, constructed from VA pharmacy claims data based on the ReComp algorithm, were assessed using generalized estimating equations.

Results: Veterans with lower comorbidity were more responsive to a U.S.$5 copayment increase than higher comorbidity veterans. In the lower comorbidity groups, veterans with diabetes had a greater reduction in adherence than veterans with hypertension. Adherence trends were similar for copayment-exempt and nonexempt veterans with higher comorbidity.

Conclusion: Medication copayment increases are associated with different impacts for low- and high-risk patients. High-risk patients incur greater out-of-pocket costs from continued adherence, while low-risk patients put themselves at increased risk for adverse health events due to greater nonadherence.

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Figures

Figure 1
Figure 1
Adjusted Medication Adherence Trends for the Diabetes Cohort Note. See Appendix SA3 for Full Model Estimates.
Figure 2
Figure 2
Adjusted Medication Adherence Trends for the Hypertension Cohort Note. See Appendix SA4 for Full Model Estimates.
See this image and copyright information in PMC

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References

    1. Andrade SE, Kahler KH, Frech F, Chan KA. “Methods for Evaluation of Medication Adherence and Persistence Using Automated Databases”. Pharmacoepidemiology and Drug Safety. 2006;15:565–74. - PubMed
    1. Ash AS, Ellis RP, Pope GC, Ayanian JZ, Bates DW, Burstin H, Iezzoni LI, MacKay E, Yu W. “Using Diagnoses to Describe Populations and Predict Costs”. Health Care Finance Review. 2000;21(3):7–28. - PMC - PubMed
    1. Austin PC. “Using the Standardized Difference to Compare the Prevalence of a Binary Variable between Two Groups in Observational Research”. Communications in Statistics. 2009;38:1228–34.
    1. Baser O. “Too Much Ado about Propensity Score Models? Comparing Methods of Propensity Score Matching”. Value Health. 2006;9(6):377–85. - PubMed
    1. Benner JS, Glynn RJ, Mogun H, Neumann PJ, Weinstein MC, Avorn J. “Long-Term Persistence in Use of STATIN Therapy in Elderly Patients”. Journal of the American Medical Association. 2002;288(4):455–61. - PubMed

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