The impact of dosing frequency on medication adherence in chronic cardiovascular disease: Systematic review and meta-analysis

Introduction and Objective: Non-adherence to drug treatment is a major health problem. In Europe, it has been estimated that 9% of cardiovascular events can be attributed to non-adherence. The complexity of dosing regimens is one of the factors identified as contributing to non-adherence. In this systematic review we aimed to assess the impact of dosing frequency on adherence to drug treatment in patients with chronic cardiovascular disease. Methods: MEDLINE and the Cochrane Library (November 2013) were searched for randomized controlled trials (RCTs) comparing different dosing regimens (once-daily administration vs. two or more daily administrations) and assessing adherence to therapy in patients with chronic cardiovascular disease. Only trials with at least five months of follow-up were included. The results of the studies were pooled through a random effects meta-analysis. Relative risk (RR) and 95% confidence interval (CI) were derived. Statistical heterogeneity was calculated using the I-2 test. Results: Four RCTs (a total of 2557 patients) were included. Dosing regimens with once-daily administration were associated with a significant 56% reduction in risk of non-adherence to drug therapy (RR: 0.44; 95% CI: 0.35-0.54, I-2=25%). Conclusions: Few clinical trials have assessed the long-term impact of dosing frequency on medication adherence in chronic cardiovascular disease. The best available evidence suggests that taking medication once daily decreases the risk of non-adherence to treatment by approximately 50%. The impact on clinical outcomes remains to be established. (C) 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier Espana, S.L.U. All rights reserved.