Healthcare and Medication Adherence among Older Adults with Chronic Diseases

Older adults account for almost one-third of all medications prescribed in the US. Of special concerns are the high rates of medication non-adherence in this population. Understanding the drivers of the medication non-adherence among the older population can inform effective public health interventions. This dissertation is divided into three separate sections, and each section examines different determinants of the medication non-adherence. The first section used systematic literature review and meta-analysis to describe the prevalence of medication non-adherence and overview the association between patient-provider relationship and medication non-adherence among community-dwelling older adults. Ten studies were included in this review. The mean prevalence rate of medication non-adherence was 33%. Information exchange was positively associated with medication non-adherence, but discussion about barriers was negatively associated with medication non-adherence. The second section used multiple linear mixed-effects models to examine the long-term impacts of the Chronic Disease Self-Management Program (CDSMP) on medication non-adherence in older adults. Medication adherence did not improve significantly at the 6-month follow-up assessment (p=0.518) but improved significantly at the 12-month follow-up assessment (p=0.021). Among those with major depression at the baseline assessment, the short-term improvements in depression (p=0.002) and self- iii rated health (p=0.045) were associated with improved medication adherence at the 12-month follow-up assessment. The third section used structural equation modeling to examine the causal paths between poverty, patient attitudes, and cost-related medication non-adherence (CRN). Six percent of the participants reported CRN in the past 12-months. The final model showed a good-to-fair fit. As hypothesized, the effects of poverty on CRN was mediated through the medication affordability, access to healthcare, and overall patient satisfaction. Medication non-adherence is a complex problem that is rooted in multitudes of inter-related factors, and the three sections have examined multiple modifiable factors, suggesting several points of intervention for improving medication adherence among older adults. We call for more senior-friendly public health interventions that address the modifiable barriers (e.g., patient-provider relationship, depression, self-rated health, and patient attitudes). Future studies are needed to understand the underlying complexity and guide the future interventions