A systematic review of consistency between health literacy and adherence to Highly Active Antiretroviral Therapy (HAART)

Background Health literacy is considered as the degree to which individuals have the capacity to obtain, process and understand basic information and services needed to make appropriate decision regarding their health. Although many studies have examined the association between health literacy and medication adherence in chronic disease context, findings have been contrasting. Medication adherence among people living with HIV remains an important public health challenge, despite recent simplified drug regimens. The main purpose of this study was to review the association between health literacy and adherence to Highly Active Antiretroviral Therapy (HAART). Additionally, this review aimed to clarify whether different adherence measures could influence that relationship. Methods Literature search was performed in PubMed and Scopus for studies regarding health literacy and HAART adherence among individuals HIV infected adult published between 1999 and 2013. Papers focused on drug users, pregnant women and naive patients were excluded. Furthermore, only studies with a measurement of health literacy with validated tools were included. Reporting was conducted in the form recommended in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and checklist. Results There were 57 potentially relevant articles from which a total of 7 studies concerning an overall population of 1274 were included in the systematic review. Adherence was assessed using objective measures (pharmacy refill records, electronic event monitors and unannounced telephone-based pill counts) in three articles; others papers used self-report tools or interview. Two different validated instruments for measuring literacy were reported. In three studies participants with lower health literacy demonstrated poorer adherence compared to individuals with higher literacy (33% of all population, including 416 individuals). The association between health literacy and adherence was not related to different HAART adherence measurement. Conclusions Additional research was needed to pursue a better understanding of the mechanism by which health literacy affects medication adherence. Key message A better understanding of the impact of health literacy on medication adherence is a public health priority in order to safeguard vulnerable communities such as persons living with HIV.