Publication Date

2011-07-18

Availability

Open access

Embargo Period

2011-07-18

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Psychology (Arts and Sciences)

Date of Defense

2010-08-20

First Committee Member

Michael H. Antoni

Second Committee Member

Biing-Jiun Shen

Third Committee Member

Frank J. Penedo

Fourth Committee Member

Alan M. Delamater

Fifth Committee Member

Ray E. Hershberger

Abstract

Heart failure (HF) is a debilitating chronic illness that afflicts millions of Americans and carries a poor prognosis, likely due to insufficient medication and low-salt diet adherence, which exacerbates HF symptoms and leads to frequent rehospitalizations. Specific reasons underlying non-adherence among HF patients are unclear. Studies investigating reasons for adherence among HF patients have shown that correlates of poor adherence include demographic (i.e., age, income), functional (i.e., NYHA), and psychosocial (i.e., social support, depression) variables. Research studies among individuals with chronic diseases suggest that an individual’s beliefs about medicines may explain adherence, but this research is limited among HF patients. The purpose of this study was to examine how psychosocial variables and beliefs about medicines are related to self-reported medication and low-salt diet adherence among individuals with HF, while controlling for demographic and physical functioning variables. This study had three aims: 1) To examine the relationships between psychosocial variables (e.g., depression, hostility, social support) and adherence; 2) To examine the relationship between beliefs about medicines and adherence; and 3) To investigate whether beliefs about medicines moderate the relationship between psychosocial variables and adherence. An ethnically-diverse sample of 105 HF patients completed several measures assessing depressive symptoms, level of hostility, perceived social support, beliefs about medicines, and medication and low-salt diet adherence. Structural equation modeling revealed that higher depression, higher hostility, and a stronger belief that medications are harmful and/or overused by doctors were significantly related to worse medication adherence. Further, participants who believed that medicines are necessary and had few concerns about them were more likely to adhere to a low-salt diet. Age, income, and number of co-morbid illness also were significantly related to low-salt diet adherence beyond contributions of beliefs about medicines scales and psychosocial variables. Thus, overall it appears that different beliefs about medicines differentially influence medication versus low-salt diet adherence, and psychological disposition may not underlie low-salt diet adherence. These results can inform interventions of health care practitioners in addressing adherence issues with HF patients.

Keywords

medication adherence; diet adherence; heart failure; beliefs about medicines; depression; hostility

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