Almost a quarter of people over the age of 40 take five or more prescription medications. Taking this many medications can lead to drug interactions, adverse side effects, more frequent office visits, and even hospitalizations.
What’s most alarming, studies suggest this prescribing cascade increases the risk of dementia. Could the pattern of taking multiple prescription drugs in the years before a dementia diagnosis give clues about what lies ahead?
The World Health Organization regards polypharmacy as a major challenge to address. They’ve made it a goal to cut in half the incidences of severe, avoidable, medication-related physical harm in the years ahead. Boy, do they have their work cut out for them.
Drugs for treatment and prevention
These days many of the drugs taken by people in middle age and beyond aren’t for the treatment of illnesses but for the prevention of a range of conditions. I’m talking about drugs like statins or blood thinners and blood pressure medications to prevent heart disease. This increases the risk of physical harm even further.
In fact, patients requiring hospital treatment who take multiple medications have a higher likelihood of re-admission within three months after discharge and have more than double the risk of death. One type of drug is of particular concern when it comes to the risk of dementia.
Anticholinergic medications are used to manage and treat respiratory disorders, cardiovascular disease, bladder conditions, gastrointestinal problems, and other diseases. They are therefore in widespread use. They include everything from Glycopyrrolate (Robinul) to Benadryl.
A review of 18 studies containing 124,286 participants published in 2015 found that drugs with anticholinergic effects increase the risks of cognitive impairment, falls and all-cause mortality in older adults.
A major study published four years later involving over 300,000 seniors strongly linked some types of anticholinergics to future dementia. And yet this is just one class of drug among many that are commonly prescribed in adults, especially older adults.
To understand how medication use evolved in dementia patients, a research group led by the University of Plymouth in England decided to investigate the pattern of prescribing during the years before diagnosis.
Polypharmacy is common prior to diagnosis
The team used machine learning techniques to identify clusters of polypharmacy – meaning the simultaneous use of three or more prescription drugs – in 33,451 patients subsequently diagnosed with dementia. They went back 20 years before the participants’ diagnoses and divided this time frame into four periods of five years. The results were published in the journal Aging and Disease last October.
Their analysis showed that leading up to the dementia diagnosis, the proportion of patients taking three or more medications rose from 5.5 percent sixteen to twenty years out, to 82.16 percent less than five years from diagnosis.
The team also identified patterns of medication use becoming increasingly similar as patients approached the date of diagnosis. That’s when the medications shifted from being prescribed for a variety of unrelated conditions to being targeted at very specific medical conditions.
For instance, in the closest four-year period to dementia diagnosis there were three clusters of polypharmacy, of which two were sizable. Two-thirds of patients were taking medicines for respiratory and urinary infections, arthritic and rheumatic conditions, and cardiovascular disease. Another quarter took medicines for infections, arthritic and rheumatic conditions, cardio-metabolic disease, and depression.
Can make symptoms of illness worse
Perhaps most disturbing, among all three polypharmacy clusters, the researchers identified medications known to interact with each other or worsen symptoms of other chronic conditions.
Since the study only included dementia patients, there’s no way of knowing if the prescribing pattern is predictive for dementia.
However, the researchers hope by identifying patterns before diagnosis, it will, they write, “provide insights into the impacts of polypharmacy on development of dementia, or opportunities for early intervention in prescribing, and support the identification of medications at risk of drug-drug interactions.”