Diffusion of Prescription Drugs for Alzheimer's disease among Medicare Beneficiaries
Open Access
- Author:
- Ganesh, Chandrakala
- Graduate Program:
- Health Policy and Administration
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- August 25, 2009
- Committee Members:
- Dennis G Shea, Dissertation Advisor/Co-Advisor
Dennis G Shea, Committee Chair/Co-Chair
Pamela Farley Short, Committee Member
Rhonda Belue, Committee Member
Donna Marie Fick, Committee Member - Keywords:
- Medicare
Alzheimers disease
diffusion
prescription drugs - Abstract:
- This dissertation is centered on Alzheimer’s disease (AD), the most common type of dementia that is characterized by memory loss and inability to carry on everyday activities. While there is no cure for AD, five drugs have been approved to date for the management of Alzheimer’s symptoms. The first AD drug Cognex®, became available in 1993. Subsequent AD drugs, Aricept®, Exelon®, Reminyl®, and Namenda® were introduced in 1996, 2000, 2002 and 2003 respectively. New drug treatments for AD offer the opportunity to study diffusion of a new technology and its impact on health care disparities and health care costs. There is little nationally representative information available on individuals who use AD drugs. This study explored several issues related to AD prevalence, costs and treatment among older adults. There were three main objectives of this dissertation. The first objective was to determine the trends in the prevalence of AD, the use of AD drugs, and spending by Medicare beneficiaries with AD. The second objective was to determine the factors influencing AD drug treatment of Medicare beneficiaries over time during the study period. The third objective was to determine the disparities in use of AD drugs among Medicare beneficiaries. The data used for the study includes both survey and claims data of beneficiaries from the Medicare Current Beneficiary Survey from years 1993 to 2003. The conceptual models used included a modified version of the Roger’s diffusion model and the Institute of Medicine’s disparities model. Analysis for the first research objective was primarily descriptive. Linear probability models were used to estimate predictors of AD drug use and Oaxaca decomposition methods were used to estimate disparities in AD drug use among Medicare beneficiaries with AD. Descriptive analysis showed that beneficiaries who were diagnosed with AD grew by 70 percent between 1993 and 2003. The use of AD drugs among beneficiaries with AD grew 100-fold during the study period. Aricept® was the most widely used drug, and contributed to about 80 percent of the total AD drug use in 2003. The mean total spending on all prescription drugs (including AD drugs) by Medicare beneficiaries with AD was $2,308 in 2003, a three-fold increase over mean spending in 1993. The mean spending on AD drugs alone increased by 400 percent; from $157 in 1993 to $803 in 2003. Regression models determined that blacks, rural beneficiaries and those with higher incomes were not less likely to receive AD drug treatment compared with whites, urban beneficiaries and those with lower incomes, respectively. Analysis of time trends indicated that AD drug use is likely to increase over time among Medicare beneficiaries. Differences in AD drug use over time were observed by race and metro status across individuals. However, no significant differences were observed in AD drug use over time by income categories. Models estimating disparities in AD drug use indicated that significant racial and income disparities existed in AD drug use among Medicare beneficiaries. However, no significant rural-urban disparities in AD drug use were observed. This dissertation provides health policy makers with an understanding of how health care access, technology, costs and disease prevalence may be related when using health care claims data. It has important implications for persons with AD and their families, disparities research, and government programs such as Medicare and Medicaid Health services researchers can build on this study and identify potential areas of research to influence policy decisions and health care practice.