Mediation effects of medication information processing and adherence on association between health literacy and quality of life

BACKGROUND: To examine whether medication related information processing defined as reading of over-the-counter drug labels, understanding prescription instructions, and information seeking—and medication adherence account for the association between health literacy and quality of life, and whether these associations may be moderated by age and gender. METHODS: A sample of 305 adults in South Korea was recruited through a proportional quota sampling to take part in a cross-sectional survey on health literacy, medication-related information processing, medication adherence, and quality of life. Descriptive statistics and structural equation modeling (SEM) were performed. RESULTS: Two mediation pathways linking health literacy with quality of life were found. First, health literacy was positively associated with reading drug labels, which was subsequently linked to medication adherence and quality of life. Second, health literacy was positively associated with accurate understanding of prescription instructions, which was associated with quality of life. Age moderation was found, as the mediation by reading drug labels was significant only among young adults whereas the mediation by understanding of medication instruction was only among older adults. CONCLUSION: Reading drug labels and understanding prescription instructions explained the pathways by which health literacy affects medication adherence and quality of life. The results suggest that training skills for processing medication information can be effective to enhance the health of those with limited health literacy.