Effectiveness and content analysis of interventions to improve medication adherence in hypertension: a systematic review

Abstract

Background.Hypertension control through pharmacological treatment has led to benefits in the prevention of morbidity and mortality from cardiovascular diseases. However, evidence suggests that as many as 50% to 80% of patients treated for hypertension are have low adherence to their treatment regimen. The objective of this systematic review is to evaluate the effectiveness of medication adherence interventions for hypertension. In addition we aim to explore what barriers and facilitators in the interventions may have been targeted and how these might be related to the effect size on BP. Methods.This review is a hypertension-specific update to the previous Cochrane Review by Nieuwlaat et al. (2014) on interventions to enhance medication adherence. A systematic literature search was carried out and two authors independently screened titles and abstracts. A meta-analysis was conducted and theoretical factors in interventions were identified using the Theoretical Domains Framework. Findings.Seventeen RCTs were identified for inclusion. There was significant heterogeneity in sampling, measurement, intervention approaches and analytical approaches among the identified studies. These included interventions employing combination pills, self-monitoring of BP and mHealth components. The most common theoretical domains targeted were ‘Environmental Context and Resources’ (87.0% of studies), ‘Memory, Attention and Decision Processes’ (82.6% of studies) and ‘Social Influences’ (60.9% of studies). Several individual domains and clusters of domains were associated with outcomes in univariate analyses. Conclusions.Understanding whether adherence enhancing interventions are effective and which theoretical components are involved can inform future interventions and practice. The next stage of this study will involve further quantitative synthesis of these studies.