Predictors of β-blocker adherence in cardiac inherited disease

OBJECTIVE: The cardiac inherited disease (CID) population has suboptimal adherence to long-term β-blocker therapy, which is known to be a risk for sudden cardiac death. This study aimed to identify the clinical and psychosocial variables associated with non-adherence in this population. METHODS: 130 individuals (aged 16–81 years, median: 54) from the New Zealand Cardiac Inherited Disease Registry taking β-blockers participated: 65 (50%) long QT syndrome, 42 (32%) hypertrophic cardiomyopathy and 23 (18%) other. Participants completed one questionnaire recording self-reported adherence, anxiety, depression, confidence in taking medication, illness perceptions and medication beliefs. Demographic and clinical variables were taken from the registry. RESULTS: 21 participants (16%) were classed as non-adherent. Bivariate analysis showed that self-reported adherence was worse in those who were younger (p<0.001), had a channelopathy not cardiomyopathy (p<0.01), reported lower confidence in taking β-blockers (p<0.001), had high concerns (p<0.05) and low necessity beliefs about their β-blocker (p<0.001), a poorer understanding of their CID (p<0.01), and lower treatment control beliefs (p<0.01). These variables accounted for 37% of the variance in adherence in a linear regression model. Stronger beliefs around medication necessity and higher confidence in their ability to take their medication predicted β-blocker adherence. CONCLUSIONS: Factors associated with β-blocker non-adherence in patients with CID include young age, having a channelopathy, negative medication beliefs, low confidence in taking medication and poor illness perceptions. These findings present an opportunity to develop targeted interventions to improve adherence.