In the five years prior to being diagnosed with dementia, patients commonly have prescriptions for three or more drugs to treat multiple health conditions. The corresponding study was published in Aging and Disease.
Previous studies have found that multiple prescriptions for preventative medications may reduce their individual benefits and increase the possibility of harm from drug interaction and side effects. Other research indicates that those taking multiple medications who require hospital treatment are more likely to be re-admitted within three months of being discharged.
"Given the rise in dementia cases internationally, the need to understand how patterns of polypharmacy evolve before and after a dementia diagnosis are important for devising a safe treatment programme for each patient,” said Shangming Zhou, Professor of e-Health at the University of Plymouth, lead author of the study.
“Our aim in this study was to help doctors find ways to prescribe multiple items of dementia medication safely and without reducing their effectiveness. The use of machine learning has been vital in helping us understand how these patterns develop, and our hope is we can now use this knowledge to treat patients,” he added.
For the current study, researchers analyzed health data from 33,451 dementia patients in Wales. Data included medicine use every five years for 20 years prior to dementia diagnosis. Whereas just 5.5% of patients were prescribed three or more medications 16-20 years before dementia diagnosis, 82.16% of patients were prescribed three or more medications within five years of diagnosis.
In the five years prior to dementia diagnosis, the researchers noted three distinct clusters of polypharmacy. The first, comprising 66.55% of patients, took medications for respiratory/ urinary infections, arthropathies and rheumatism, and cardiovascular disease. The second, including 22% of patients, took medicines for infections, arthropathies and rheumatism, cardio-metabolic disease, and depression.
The third group, comprising 2.6% of patients, took medicines for arthropathies, rheumatism, and osteoarthritis. The researchers noted that the closer to dementia diagnosis patients were, the more health conditions tended to cluster together. However, the further patients were from diagnosis, the more likely the occurance of health conditions were to be clearly distinct from each other.