Abstract
BACKGROUND: Medication adherence in heart failure (HF) is a crucial but poorly understood phenomenon. The purpose of this study was to explore factors contributing to medication adherence in patients with HF by using the World Health Organization's multidimensional adherence model. METHODS AND RESULTS: Patients (N = 134) with HF (70% were male, aged 61 +/- 12 years, 61% with New York Heart Association III/IV) were studied to determine the predictors of medication adherence derived from the multidimensional adherence model. Medication adherence was measured objectively using the medication event monitoring system for 3 months. Three indicators of adherence were assessed by the medication event monitoring system: 1) dose-count, the percentage of prescribed doses taken; 2) dose-days, the percentage of days the correct number of doses were taken; and 3) dose-time, the percentage of doses that were taken on schedule. Barriers to medication adherence, ethnicity, and perceived social support predicted dose-count (P < .001). New York Heart Association functional class, barriers to medication adherence, financial status, and perceived social support predicted dose-day (P < .001). Barriers to medication adherence and financial status predicted dose-time (P = .005). CONCLUSION: A number of modifiable factors predicted medication adherence in patients with HF, providing specific targets for intervention.