Medication adherence interventions for heart failure patients: A meta-analysis

BACKGROUND: Adherence to medications is an essential part of heart failure self-care. Poor medication adherence leads to increased rates of exacerbation causing hospitalizations and increased morbidity and mortality. AIMS: This meta-analysis aimed to quantify the effect of interventions to improve adherence to heart failure medications on adherence outcomes. METHODS: Comprehensive search methods identified studies testing interventions designed to improve medication adherence among patients with heart failure. Data from eligible studies were independently coded by two coders and analyzed using random-effects meta-analysis methods. Moderator analyses to explain heterogeneity among the studies were conducted using meta-regression and ANOVA for moderators with sufficient numbers of comparisons. RESULTS: Searching yielded 6665 potential study reports. From these studies, we identified 29 eligible treatment versus control comparisons of heart failure medication adherence interventions (total n=4285). The mean effect size (d-index) for two-group comparisons was 0.29 (SE=0.09, p=0.004). Moderator analyses found effect sizes were larger as samples were older. Medication adherence effect sizes were larger for studies conducted in Europe or Asia versus North America, and for interventions focused on changing only medication adherence. Smaller effect sizes were seen for interventions with components directed at health care providers, and those including social support as an intervention component. CONCLUSION: While the medication adherence effect size across all studies was significant, the effect was modest. Approaches to improving heart failure medication adherence may be most effective when focused on medication adherence alone, and when seeking to change behavior of patients, rather than health care provider behavior.