Literacy, self-efficacy, and HIV medication adherence

https://doi.org/10.1016/j.pec.2006.08.006Get rights and content

Abstract

Objective

We examined the relationship between patient literacy level and self-reported HIV medication adherence, while estimating the mediating roles of treatment knowledge and self-efficacy on this relationship.

Methods

Structured patient interviews with a literacy assessment, supplemented by medical chart review, were conducted among 204 consecutive patients receiving care at infectious disease clinics in Shreveport, Louisiana and Chicago, Illinois. Literacy was measured using the Rapid Estimate of Adult Literacy in Medicine (REALM), while the Patient Medication Adherence Questionnaire (PMAQ) was used to assess medication self-efficacy and adherence to antiretroviral regimens in the past 4 days.

Results

Approximately one-third of patients (30.4%) were less than 100% adherent to their regimen, and 31.4% had marginal to low literacy skills. In multivariate analyses, low literate patients were 3.3 times more likely to be non-adherent to their antiretroviral regimen (p < 0.001). Patients’ self-efficacy, but not knowledge, mediated the impact of low literacy on medication adherence (AOR 7.4, 95% CI 2.7–12.5).

Conclusion

While low literacy was a significant risk factor for improper adherence to HIV medication regimens in our study, self-efficacy mediated this relationship.

Practice implications

Comprehensive intervention strategies that go beyond knowledge transfer may be needed to address self-efficacy among patients across all literacy levels to be successful in the management of difficult medication schedules.

Introduction

The prevalence and consequences of poor HIV medication adherence have been repeatedly documented in the literature, and adherence has been linked to specific patient and regimen characteristics [1], [2], [3], [4]. Literacy may play a role; previous studies have shown that persons with low literacy skills are more likely to possess a poor working knowledge of HIV and its treatment [5], [6], [7], [8], [9]. According to the Institute of Medicine, 90 million people in the United States lack the literacy proficiency needed to properly understand and act on health information [10]. This has often been referred to as health literacy; a reflection of both a patient's ability and the literacy prerequisites of the healthcare system. Low-income individuals, ethnic minorities, and persons in rural areas are disproportionately hindered by literacy barriers and therefore face significant health literacy barriers as well [11].

The direct relationship between patient literacy and HIV medication adherence behavior has received limited attention. Kalichman et al. found that infected patients with limited literacy had less general knowledge of the disease and their own treatment compared to patients with adequate literacy skills, and were less likely to have an undetectable viral load [5], [6]. Yet other studies reporting an association between literacy and treatment knowledge have either failed to report or did not find a significant association between low literacy and improper adherence to medication regimens [7], [8].

Self-efficacy related to managing medications may help explain why many lower literate patients may not adhere to their antiretroviral regimen. Self-efficacy refers to an individual's own perceived ability to perform a specified behavior or set of behaviors. This is a construct central to Social Cognitive Theory, which proposes that behaviors are determined not solely by knowledge, but rather by the outcome and efficacy expectations related to performing them [12], [13]. Outcome expectations refer to an individual's perceptions about whether behaviors will lead to certain outcomes, while efficacy expectations (self-efficacy) refer to the individual's beliefs about whether he or she can successfully enact the behavior in question. Self-efficacy has been previously investigated in a variety of contexts and settings; it has been repeatedly shown to predict the likelihood of initiating communication [14], adjusting to illness and treatment [15], [16], [17], and engaging in recommended health behaviors [18], [19]. Self-efficacy has also been proposed as a mediating factor between educational attainment and health behaviors [20], [21].

We have previously reported low literacy to be a significant independent predictor of HIV treatment knowledge and correct identification of medications in one's current regimen among a diverse cohort of patients in Chicago, Illinois and Shreveport, Louisiana. For the present study, we sought to investigate among this same cohort of patients: (1) the relationship between limited literacy and HIV medication adherence; and (2) whether HIV treatment knowledge, self-efficacy, or both mediated the literacy-adherence relationship.

Based on prior studies examining the relationship between literacy and health outcomes [22], and common proposed pathways for how literacy might impact HIV medication adherence [23], we hypothesized that limited literacy would directly influence both patients’ knowledge of their treatment regimen and self-efficacy to properly manage medication schedules. Combined, knowledge and self-efficacy are likely to empower individuals to engage in the recommended health behaviors associated with proper administration and adherence to prescribed antiretroviral regimens [24]. While other variables (e.g., culture, socioeconomic resources) may factor into literacy, self-efficacy, and treatment knowledge, we specifically sought to examine the proximal relationships between these variables in this study.

Section snippets

Sample

The study sample and methods have been previously described in detail [9]. From June to September 2001, we enrolled a total of 204 consecutive HIV-infected patients receiving medical care who were prescribed one or more antiretroviral medications and received medical care through outpatient infectious disease clinics at the Northwestern Memorial Hospital (Chicago site) and the Louisiana State University Health Sciences Center at Shreveport (LSUHSC). Patients who had been on their current

Sample characteristics

The mean age of respondents was 40.1 years (S.D. = 9.2 years), 45.1% of the patients were African-American and 79.9% were male. More than half of respondents (55.9%) were unemployed, 39.7% had a household income less than $800/month, and 27.5% did not carry any health insurance. Over 60% of patients reported at least some college education. Approximately one-third of patients had limited literacy skills; 11.3% were reading at or below a 6th grade level (low literacy) and 20.1% were reading at a

Discussion

We recruited patients from two regions of the United States to examine the relationship between literacy and adherence to HIV antiretroviral medications. Nearly one-third of patients in our sample were less than 100% adherent to their HAART regimen, and patient literacy level was associated with more than a three-fold greater likelihood of missed doses. This provides general support for previous findings that documented the association between limited literacy and improper adherence to

Acknowledgement

Dr. Wolf is supported by a Centers for Disease Control and Prevention Career Development Award (K01 EH000067-01).

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