Title: Impact of Out-of-pocket Pharmacy Costs and Medicare Part D on Medication Adherence among Adults with Diabetes
Description: Significant out-of-pocket spending to afford medications to control blood glucose in elderly people with diabetes is one of the chief challenges to medication adherence. In an effort to reduce the financial burden of prescription drugs on the elderly, Medicare Part D was created and went into effect in 2006. However, one in four Medicare Part D beneficiaries experiences a coverage gap where they must pay 100% of total prescription drug costs. Approximately a quarter of those individuals discontinued their drugs when they reached the coverage gap. Currently, with the Patient Protection and Affordable Care Act of 2010, the coverage gap will be eliminated by 2020. This dissertation examines which factors affect medication adherence in adults with diabetes (Aim 1) and whether the recent policy effort of Medicare Part D effectively decreases the financial burden of prescription drugs on the elderly with diabetes (Aim 2). Chapter One provides the significance of out-of-pocket costs for medication adherence in elderly individuals with diabetes as well as background information on Medicare Part D and its coverage gap.

Chapter Two reviews the literature to synthesize current knowledge that has informed the methodology for this dissertation. This chapter also identifies gaps in this body of work. These include comparing advantages and disadvantages of medication adherence as measured by patient self-report, pharmacy refills, and electronic lids on medication containers. Two systematic reviews are conducted in order to determine the most commonly used measurements and definitions of medication adherence measured by pharmacy claims data, and to identify barriers to and facilitators of medication adherence among adult diabetes patients. Lastly, previous studies that focused on the impact of Medicare Part D and its coverage gap on out-of-pocket pharmacy costs and medication adherence are reviewed. Chapter Three describes the methodologies to address Aims 1 and 2 including the study design, information on the data source, sample descriptions, a conceptual framework, study variables and analytic plans. Chapter Four presents key findings of this study, and Chapter Five concludes with summaries and interpretations of the findings, implications for practice and policy, and recommendations for future research.