High burden of non-adherence to blood pressure-lowering medications: meta-analysis of data from over 34,000 adults with hypertension in Sub-Saharan Africa

Abstract

Introduction: Non-adherence to blood pressure (BP)-lowering medication is a strong predictor of poor BP control. Sub-Saharan Africa (SSA) has extremely low BP control rates (~10%), but it is unclear what the burden of medication non-adherence among Africans with hypertension is. This systematic review estimated the prevalence and determinants of non-adherence to BP-lowering medications in SSA. Methods: Multiple databases were searched from inception to 6 December 2023. Two reviewers performed independent screening, extraction, and quality assessment of studies. We pooled the prevalence estimates using random effects meta-analyses and summarized the determinants using a narrative synthesis. Results: From the 1,307 records identified, we included 95 studies published between 1995 and 2023. The overall prevalence of non-adherence to BP-lowering medication among 34,102 people treated for hypertension in 27 countries was 43.5% (95% confidence interval 39.4 to 47.6; I2 = 98.3%). There was no change in the prevalence of non-adherence over time. The burden of non-adherence varied by measurement method (p = 0.028) and by median age (38.8%, > 57 years vs. 47.9%, ≤ 57 years; p = 0.015). Socioeconomic and patient-related factors were the most frequent factors that influenced medication adherence. Active patient participation in management, accurate perceptions, and knowledge of hypertension and its treatment predicted good medication adherence, whereas high pill burden, medication cost, side effects, and comorbidities predicted poor adherence. Conclusions: With the African population projected to increase from 1.4 to ~2.5 billion by 2050, targeted strategies are urgently needed to optimise medication adherence in people with hypertension in SSA.