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

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. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial This study is not a clinical trial, hence such registration was not required. ### Funding Statement None. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This is a systematic review of published research. Hence no IRB approval was required. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as [ClinicalTrials.gov][1]. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes [1]: http://ClinicalTrials.gov