Polypharmacy: Patterns and Policy Propositions

Sixty percent of U.S. adults report frequent use of prescription medications, a prevalence that is higher than ever before. Although medications are lifesaving when used properly, they can produce side effects ranging from minor problems like dizziness to severe events such as an increased risk of cancer. Polypharmacy – a phenomenon typically defined as concurrent use of multiple medications – may present unique risks for medication side effects, amplifying the effects of each of the medication in a set. Given the growing medication use across the country, this dissertation examined the causes of polypharmacy and the consequences of concurrent use of medications with side effects on population health and health care use. The first chapter provided background information on polypharmacy and medication side effects. The second chapter used the National Health and Nutrition Examination Survey (NHANES) to investigate whether and how the introduction of Medicare Part D, a large and sudden change to health care financing for Medicare beneficiaries, affected medication use for older adults. While Part D increased the use of lifesaving medications, it also increased polypharmacy. The third chapter used the NHANES to show that concurrent use of three or more medications with cognitive impairment side effects among U.S. older adults increased three-fold in the past two decades. Individuals who used three or more such medications experienced increased risks of cognitive deficits compared to non-users. The fourth chapter used the Medical Expenditure Panel Survey (MEPS) to document a growth of 36% in the concurrent use of at least three medications with mental health side effects among U.S. adults in the past two decades. Concurrent use of these medications was associated with an increase in psychiatric symptoms and the use/costs of mental health services. In the fifth chapter, I discussed how the processes of medicalization and pharmaceuticalization contributed to rising medication use and disparities in such use, which in turn had implications for population-level health disparities. Collectively, these findings shed light on patterns and disparities in population health associated with polypharmacy and speak directly to the role of broader social, economic, cultural, and institutional inequalities in generating and maintaining health disparities