Abstract 2233: Biobehavioral Factors and Heart Failure Medication Adherence

Abstract

Background: Medication adherence in heart failure (HF) patients reduces hospitalizations and improves outcomes, yet it is variable. This study evaluated adherence rates and associated biobehavioral factors for two HF medications using objective (Medication Event Monitoring System; MEMS) and self-report approaches. Methods: The sample (n = 87) was primarily male (64.4%), Black (64.7%), NYHA class II (71%), married (56.9%) with left ventricular ejection fraction (LVEF) 26.6±14.2, age 55.5±10.4 years. Adherence for a HF medication and diuretic was monitored for 19.6 ±5.7 days using the MEMS. Relationships among clinical variables (NYHA class, LVEF, six-minute walk test [6MWT]; objective (MEMs) and self-reported (Morisky Medication Adherence Scale) medication adherence; medication self-efficacy (Perceived Self-Efficacy [SE] for Medication Compliance); medication taking self-regulation (Treatment Self-Regulation for Medication Taking); and HF knowledge (HF Knowledge Questionnaire) were analyzed using correlation coefficients and hierarchical multiple regression. Results: Adherence was 85.42% for the HF medication (n=74) and 83.42% (n=67) for daily diuretic. MEMS and Morisky scores were correlated for the HF medication (r=.389, p=.002) and diuretic (r=.392, p=.002). Medication SE was related to adherence for HF medication (r=.283, p=.025) and diuretic (r=.294, p=.028). Higher HF Knowledge Questionnaire scores were related to greater adherence for the HF medication (r=.316, p=.012) and diuretic (r=.359, p=.007). The model (marital status, HF knowledge, medication SE and 6MWT) yielded adj. R 2 =.26 (F =6.7, p<.001;) with medication SE (p<.001) and 6MWT (p=.053) as independent predictors of medication adherence. Clinical, demographic and medication self-regulation variables were not significant. Conclusions: Medication adherence in HF patients is related to modifiable factors of medication self-efficacy and HF knowledge. Improving medication self-efficacy, knowledge and showing patients tangible evidence of improvement in physical function such as increased 6MWT distance may lead to enhanced medication adherence.