The majority of elderly dementia patients — about 70% — are placed on long-term courses of drugs to treat the brain disease, despite scant evidence they provide benefits beyond a year.

That’s according to a new analysis of data from Medicare Advantage enrollees, released Tuesday by the AARP Public Policy Institute. Some patients took these drugs for as long as a decade, at a cost upward of $20,000 per individual.

“Our research shows some healthcare providers continue prescribing dementia drugs to patients for much longer than is supported by the clinical evidence,” Elizabeth Carter, senior health services research advisor, AARP Public Policy Institute, and co-author of the study, said in a press release. “Not only do these drugs carry potential side effects, they are costing both patients and the healthcare system a lot of money.”

Cholinesterase inhibitors and memantine are the two drugs approved by the FDA to treat dementia symptoms, AARP notes. But benefits of those drugs are “modest,” it notes, displaying little effect on the underlying causes of dementia, or on slowing the rate of cognitive decline.

Researchers analyzed claims data from 36,000 Medicare Advantage enrollees for treatment provided between 2006 and 2015. Seventy-percent of patients taking dementia drugs received them for 13 months or longer, they discovered.

One potential avenue for follow up, Carter said, is exploring how prescribing habits differ between various healthcare settings. She urged nursing home administrators to take this information seriously and find ways to adjust how dementia treatment is provided.

“Our results are part of a larger problem that is pervasive throughout the healthcare systems — the potential overuse of healthcare services that can lead to unnecessary healthcare costs,” she told McKnight’s. “Those who operate SNFs and nursing homes are uniquely positioned to help keep an eye on their residents’ care and encourage and empower them and/or their caregivers to maintain open dialogues … to ensure their care still fits their health needs.”