Hypertension (HTN) is a Public health concern around the globe that affects around 40% the world’s population aged 25 years and older (Alwan, 2011; WHO, 2013). Antihypertensive medication adherence is fundamental in controlling blood pressure. Evidences on patients with different chronic illness have linked patients’ beliefs about health and illness to their adherence with medications. In hypertension, several quantitative studies, have found that patients’ health beliefs have an influence on medication adherence (Ambaw, Alemie, W/Yohannes, & Mengesha, 2012; Bhandari, Sarma, & Thankappan KR, 2011; Forsyth, Schoenthaler, Chaplin, Ogedegbe, & Ravenell, 2014; Kamran, Ahari, Biria, Malepour, & Heydari, 2014) however, no review to summarize and synthesize findings of those studies have established to date. Reviews of literature related to medication adherence in hypertension have only focused on barriers to antihypertensive medication adherence, where they have limited focus on patients’ beliefs as main barriers to adherence (AlGhurair, Hughes, Simpson, & Guirguis, 2012; Khatib et al., 2014) . Only one review has examined patients’ beliefs in relation to antihypertensive medication adherence (Marshall et al., 2012); however, this review was limited to qualitative studies.
Objective: this systematic review was conducted to review quantitative studies to identify various patients’ health beliefs of patients with hypertension and to identify the nature of the relationship of theses beliefs to medication adherence.
Method: This review was conducted using PubMed, CINHAL, EMBASE, and PsychInfo databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The following Medical Subject Headings (Mesh) and text-words were used in PubMed:
adherence [tw] OR compliance [tw]) AND (attitude*[tw] OR belief*[tw] OR perception*[tw] OR perceiv*[tw] OR psychosocial [tw]) AND ("Antihypertensive Agents"[Mesh] OR "Antihypertensive Agents" [Pharmacological Action] OR antihypertensive agent*[tw] OR medication*[tw]) AND (hypertension [tw] OR hypertensive [tw]. The search was limited to English, peer-reviewed, and full text research articles with no limitations on geographical location, year of publication, or type of patients’ beliefs as the purpose of this review to include all possible studies matching the purpose of this review. Studies were included only if they are quantitative, conducted in patients with hypertension and no other comorbidities and receiving at least one antihypertensive medication; These studies should measure medication adherence as an outcome variable and address patients’ beliefs. Studies were excluded if they have focused on providers’ beliefs rather than patients’ beliefs. After articles’ titles, abstracts, and full text screening, data from the included articles were extracted in a table. Quality of the studies was examined using Quality Assessment Tool for Systematic Review of Observational Studies (QATSO) checklist (Wong, Cheung, & Hart, 2008) that was slightly modified to fit the review. No studies were excluded based on quality evaluation.
Results: the initial search has identified 1,388 articles. After screening and removal of duplicates, a total of 25 articles were included in the review. These 25 articles appeared between 1980 and 2016, included a sample size ranging from 45 to 1,367 and represented 14 countries across Europe, Americas, Asia, Australia, and Africa.. Generally, findings of those studies indicated that patients’ health beliefs have a negative, positive, or no significant relationship with adherence to antihypertensive medications. The most identified beliefs were categorized under the following 1) beliefs about hypertension, 2) beliefs about antihypertensive medications, and 3) other patient-related beliefs. Specifically, the review has found that medication adherence was significantly higher with fewer perceived barriers to adherence such as, side effects, bad taste, and high cost and with higher self-efficacy. When examining the relationship of beliefs about medication effectiveness and necessity and beliefs about hypertension severity and susceptibility with medication adherence, the findings were mixed. Other patient- related beliefs were reported to influence medication adherence were self-efficacy, internal locus of control, subjective norms, perceived stress, and family support.
Conclusion: findings of this review are consistent with other review that examined beliefs in relation to adherence in patients with chronic illnesses. Findings indicated that some beliefs are positively related to adherence, some negatively related to adherence and some have mixed results, which indicate that findings could vary from one culture to another. Therefore, attention to patients’ beliefs should be considered by clinicians and researchers in order to improve medication adherence. Moreover, they should account for the variability of the beliefs between and within cultures that might require different strategies to enhance adherence.
