Gabapentin prescription and health-related outcomes in older adults - Project Summary/Abstract Gabapentin, currently approved to treat partial seizures and postherpetic neuralgia, was the 6th most commonly prescribed medication in the US in 2018. Notably, close to 95% of gabapentin prescriptions are for off-label indications, such as neuropathic pain, migraines, substance use disorder, and psychiatric symptoms. Gabapentin's widespread use may be driven by a belief that it is a safer drug than opioids and antipsychotics. However, there is an increasing concern about the safety of gabapentin use, and several studies have reported that gabapentin has the potential for misuse and abuse. In particular, although gabapentin prescription has dramatically increased in older adults, our understanding of gabapentin use in this population is limited. Due to gabapentin's known binding site, alpha-2-delta-1, which has a relationship with calcium channel, NMDA receptor, and thrombospondin, it is possible that gabapentin could affect older adults' cognition and motor functions. To fill in the research gap, this study proposes to assess longitudinal patterns of gabapentin use in older adults and to estimate the risk of health-related outcomes associated with gabapentin prescriptions using Medicare claims data and linked Rush Alzheimer Disease Center-Medicare data. Aim 1 will determine the distinct patterns (e.g., duration of use, concurrent medications, history of medication prior to gabapentin initiation) of gabapentin use and examine the factors, including demographics and medical history, associated with each pattern. This aim will provide clinically relevant characteristics of gabapentin users to further investigate. Aim 2 will examine the association of gabapentin use with health-related outcomes, including falls, fractures, neurocognitive changes, hospitalizations, emergency department visits, and mortality. These associations will be estimated marginal structural models by considering time-varying exposure patterns and time-varying confounders, including concurrent use of other medications and medical history. This proposal fits into the National Institute on Aging's special interest of research on pain, pain management, and opioids in aging. Through completing this project, Dr. Oh will gain experience in real-world evidence studies and expand her toolbox to serve her professional future as a neuro-pharmacoepidemiologist. Since medication use and its effects is highly influenced by policy, this project will build Dr. Oh's knowledge of the process of translating research into policy. Lastly, Dr. Oh will sharpen essential professional skills, such as grant writing, networking, and mentoring. She will be guided by a strong interdisciplinary mentoring team with collective expertise in neuroepidemiology, pharmacoepidemiology, health-related outcomes, policy, and biomedical informatics. Findings from this study will help healthcare providers and policymakers better understand the risks and benefits of prescribing gabapentin to older adults and will provide the baseline knowledge for further investigation into establishing the causal relationship between gabapentin and health-related outcomes.
