A Systematic Review of Factors Influencing Medication Adherence to Hypertension Treatment in Developing Countries

Background: Coronary heart disease (CHD), a complication of hypertension, is one of the most important and common causes of morbidity, hospitalisation, and mortality among hypertensive population. In recent decades, increased urbanisation and changes to lifestyle, diet and physical activity in developing countries have led to a major increase in the population incidence of chronic diseases including CHD. Poor medication adherence is one of the leading causes of failure to achieve hypertension control. The objective of this systematic review is to describe the prevalence of non-adherence to anti-hypertensive medications among hypertensive population in developing countries and identify factors associated with it. Methods: A literature search was conducted using the following scholarly electronic databases: Proquest, PubMed, JSTOR and Science Direct. The online search engine, Google Scholar was also used to search for and identify relevant papers. Peer-reviewed full-text articles published in English on hypertensive adults in developing countries that measured adherence to antihypertensive medications and their associations with different factors were eligible for inclusion. The review followed the PRISMA reporting and analytical guidelines for systematic reviews. Results: In all, 42 studies conducted across 19 developing countries were selected for the review. The mean prevalence of medication non-adherence (MNA) among the select hypertensive population was 47.34%. Very few studies were conducted in community settings and except for one, no study examined gender differences in MNA factors. The analysis revealed a range of factors that can influence MNA including low household income and socioeconomic status; knowledge and beliefs of hypertension and its management; avoiding side effects of medications; cost of medication; use of herbal preparations; absence of symptoms; irregular follow-up; and dissatisfaction with the treatment and health services provided. There was a general lack of consideration of role of health system in health care delivery, self-efficacy, cultural barriers, perceived individual risk of hypertension complications. There was also a lack of gender-specific research which is necessary at community settings given the social and economic vulnerabilities faced by women in developing countries that may affect adherence to antihypertensive medications. Conclusions: Future research in developing countries should consider individual risk perceptions, cultural barriers, gender and the role of local health system in health care delivery when assessing MNA among hypertensive population at community settings.