Date of Graduation


Document Type


Degree Type



School of Pharmacy


Pharmaceutical Sciences

Committee Chair

Usha Sambamoorthi

Committee Co-Chair

Aaron Metzger

Committee Member

Xiaoyun Pan

Committee Member

Cindy Tworek

Committee Member

Wenhui Wei


Parkinson's disease (PD) is the second most common neurodegenerative disease affecting an estimated one million individuals in the United States (U.S.) and five million individuals globally. With increasing age, the prevalence of PD also increases. Challenges of PD include high economic burden of formal care, informal caregiving burden, and also management of a chronic illness (e.g. type 2 diabetes mellitus) in the presence of PD. The purpose of this study was to use observational data from real-world settings to provide a comprehensive view of the burden of illness among elderly individuals with PD by assessing the formal economic burden, informal caregiving burden and the state of management of chronic illness with complexity (CIC) in the presence of two debilitating conditions (PD and type 2 diabetes mellitus). This study used a triangulation approach by using three different datasets: (i) National Medicare 5% sample claims database to evaluate the formal economic burden; (ii) the National Alliance for Caregiving (NAC) data to assess the informal caregiver burden; and (iii) the nationwide claims database of Humana Medicare Advantage Part D enrollees to evaluate the state of management of chronic illness with complexity. The specific aims of the three studies were: (1) among elderly Medicare beneficiaries aged 65 or older, estimate excess home healthcare use and expenditures among individuals with PD compared to individuals without PD and analyze predisposing, enabling, need factors, personal health behaviors, and external environment associated with excess home healthcare use and expenditures among individuals with PD; (2) assess the informal caregiver burden and estimate costs associated with informal caregiving burden among caregivers providing care to elderly individuals; and (3) assess process, and intermediate clinical outcomes of diabetes care among individuals with chronic illness with complexity defined as co-occurring PD and diabetes. From the results of the first study, we found that elderly Medicare beneficiaries with PD had significantly higher home healthcare use and expenditures compared to those without PD. The differences in home healthcare use and expenditures among elderly Medicare beneficiaries with and without PD were mainly explained by personal health behaviors such as baseline resource use and need factors such as physical and mental health conditions. In terms of the economic burden of informal caregiving, we did not observe a significant difference in informal caregiving costs between caregivers of elderly individuals with and without PD, despite the costs of informal caregiving for elderly individuals with PD being 1.27 times higher than those without PD. Individuals with CIC were less likely to achieve American Diabetes Association recommended annual HbA1c and lipid testing goals compared to those without CIC (T2DM without PD). However, individuals with CIC achieved glycemic and lipid control outcomes. Thus, these findings taken together underscore the advantage of using an integrated delivery system with better care coordination and providing "holistic care approach." As majority of elderly individuals with PD are community-dwelling, novel intervention techniques are needed to be developed to reduce the informal caregiving burden.