Date of Award

10-15-2009

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Educational Psychology and Special Education

First Advisor

Daphne Greenberg, Ph.D. - Committee Chair

Second Advisor

Dennis Thompson, Ph.D. - Committee Member

Third Advisor

Nannette Commander, Ph.D. - Committee Member

Fourth Advisor

Raymond Hart, Ph.D. - Committee Member

Fifth Advisor

Sunil Kripalani, M.D. - Committee Member

Abstract

AN EXPLORATORY MODEL OF MEDICATION REFILL ADHERENCE BEHAVIOR by Gayle Holmes Payne Coronary heart disease (CHD) is the leading cause of death in the United States with over 15.8 million Americans suffering from the chronic disease (U.S. Department of Health and Human Services, 2007). Adherence to medication regimens has been identified as a key mediator between medical practice and patient outcomes (Kravitz & Melnikow, 2004). In this study, participants (N = 355) with CHD completed a questionnaire measuring their background characteristics, cognitive status, health literacy skills, self-efficacy levels, their perceived concerns and necessity beliefs about medication use, and enablers and barriers to their medication-taking behavior. Information regarding each participant’s number of medications and presence of disease was obtained from medical charts. Data regarding the dependent variable, cardiovascular medication refill adherence, were collected from pharmacy records. The data were used to see how the various variables work together in a model that explains cardiovascular medication refill adherence behavior. The study aimed to contribute to the body of adherence research by jointly examining all variables found to have an association with medication adherence through a path analysis to explain the determinants of medication refill adherence behavior. Analyses indicated that the hypothesized model did not fit the data. Additional analysis was conducted using a condensed revised model (age, self-efficacy, perceived concerns and necessity) and a self-reported measure of medication adherence (Adherence to Refills and Medication Scale) as the dependent variable. The revised model fit the data, X2(5, N = 355) = 6.71, p = .24. The revised model did not explain a statistically significant amount of the variance in medication adherence, suggesting that there may be other additional factors that may mediate the relationship between independent variables and medication refill adherence. Additional research is needed to reveal all the determinants of medication refill adherence behavior and to identify the most effective measure of adherence behavior. Given the number of people who suffer from CHD, and the often low rates of medication adherence, research that continues to explore and improve medication refill adherence will have a significant impact on morbidity and mortality rates.

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