Effective treatment of HIV hinges upon maintaining adequate antiretroviral therapy adherence. Accurate, cost-effective measurement of medication adherence is needed to best respond to the HIV pandemic. The visual analogue scale (VAS) appears to be a simple and easy to use measure of adherence but the current literature on its use is mixed. This meta-analysis (1) describes VAS concordance with other measures of medication adherence and viral load; and (2) examines how research methods moderate the reported strength of the VAS–viral load relationship. Literature searches were conducted electronically and by hand with a total of 20 studies included in the present study. The VAS showed large strength associations with most other measures of adherence and a smaller association with viral load. More rigorous methodological quality significantly improved the VAS–viral load effect size. We conclude with optimization recommendations for VAS use in clinical practice and research design.
