March 10, 2020
By Julie Gould
According to study findings published online in Neurology, higher out-of-pocket costs were link with lower medication adherence among older adults with common neurologic conditions—including dementia, Parkinson disease (PD), and neuropathy.
Brian Callaghan, MD, MS, associate professor of neurology, University of Michigan, and colleagues observed 52,249 patients with neuropathy on gabapentinoids, 5,246 patients with neuropathy on SNRIs, 19,820 patients with dementia on cholinesterase inhibitors, and 3,130 patients with PD on dopamine agonists. The study authors used instrumental variable analysis to estimate the association between treatment costs and other patient factors on medication adherence.
According to the findings, when out-of-pocket costs were increased by $50, the study authors found that patients with neuropathy on gabapentinoids (adjusted incidence rate ratio [IRR] 0.91, 0.89–0.93) and dementia (adjusted IRR 0.88, 0.86–0.91) experienced significantly lower medication adherence. Increased costs for patients with neuropathy on SNRIs (adjusted IRR 0.97, 0.88–1.08) and patients with PD (adjusted IRR 0.90, 0.81–1.00) were not significantly linked with medication adherence.
In order to better understand what previous research prompted this study as well as the importance of the current findings, we spoke with Dr Callaghan.
What existing data led you and your co-investigators to conduct this research?
We had previously shown that out-of-pocket costs are on the rise for common neurologic medications over the past 15 years. For this project, we wanted to know what effect these out-of-pocket costs were having on medication adherence.
Please briefly describe your study and its findings. Were any of the outcomes particularly surprising?
We looked at the association of out-of-pocket costs on medication adherence for patients with dementia, Parkinson disease, and neuropathy using pairs of medication that had similar benefits and side effects. We showed that out-of-pocket costs not only can lead to financial harm, but that they also can lead to a predictable drop in taking medications prescribed by physicians. The surprising part was the magnitude of the association. A $50 per month out-of-pocket increase results in a 5-10% decrease in patients taking their prescribed medications.
What are the possible real-world applications of these findings in clinical practice?
Patients will take less of their prescribed medications as out-of-pocket costs continue to rise, which will likely impact their health outcomes. For example, neuropathy patients will be in more pain, Parkinson patients will have more tremor, and dementia patients will have worse memory.
Do you and your co-investigators intend to expand upon this research?
We plan to investigate the magnitude and effect of super high cost neurologic medications, which are becoming increasingly available.
Is there anything else pertaining to your research and findings that you would like to add?
Out-of-pocket costs are rising, particularly in those with high deductible plans, which are also increasing. The predictable decrease in medication adherence with even small changes in out-of-pocket costs likely has important implications for patient care. This is a new problem in the last 10 years that likely requires new health care policy solutions.
Reynolds EL, Burke JF, Banerjee M, et al. Association of out-of-pocket costs on adherence to common neurologic medications [published online ahead of print, 2020 Feb 19]. Neurology. 2020;10.1212/WNL.0000000000009039. doi:10.1212/WNL.0000000000009039