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A dementia diagnosis is more likely in people taking three or more medicines for other health conditions in the five years prior to diagnosis, study results show.
The study — led by a team from the University of Plymouth and published in Aging and Disease on 11 October 2022 — found that as a patient came closer to a dementia diagnosis, patterns of polypharmacy were linked with particular medical conditions, such as respiratory or urinary infections, rheumatism, cardiovascular disease and depression.
Using a machine learning technique known as ‘exploratory factor analysis’, the researchers analysed records of more than 33,000 dementia patients in Wales between 1990 and 2015 from the Secure Anonymised Information Linkage (SAIL) databank.
The researchers found that 82% of patients with dementia were taking three or more medicines in the five years before diagnosis. This increased from 6% of the patients in the 16–20 years before diagnosis.
Patterns in polypharmacy were found to be more pronounced closer to a dementia diagnosis, with almost two-thirds of patients taking medicines for a combination of respiratory or urinary infections, arthropathies and rheumatism, and cardiovascular disease in the five years before diagnosis.
Nearly a quarter of patients were taking medicines for infections, arthropathies and rheumatism, cardio-metabolic disease and depression in the same period.
The researchers concluded: “These varying patterns would inform ‘safe prescribing’ practice before dementia diagnosis in terms of selecting low anticholinergic burden medicines to minimise their impact on cognitive impairments.”
Commenting on the study, Heather Barry, a pharmacist from Queen’s University in Belfast, whose own research includes medication management for people with dementia, said it was not just the number of medicines that needed to be considered, but whether it was appropriate medication.
“These patients are older, they’re more likely to be multimorbid. So polypharmacy is, in itself, not surprising,” she said.
“But one of the key things we need to consider with polypharmacy is the appropriateness of the medications. Obviously, around anticholinergic medications — which we know even pre-dementia diagnosis are associated with increased risk of dementia, and post-diagnosis are associated with the decline in cognitive functions.”
She added that the research would increase awareness of these issues among prescribers, healthcare professionals and pharmacists.
“It’s highlighting all of these issues to people and shifting that focus a little bit to thinking about pre-diagnosis, as well as what happens after the diagnosis. So it emphasises, at all stages, the importance of medication review,” Barry said.
