This is the largest and most detailed study to date on long-term anticholinergic use and its relationship to dementia risk.
Anticholinergics work by blocking a chemical messenger, or neurotransmitter, called acetylcholine that transmits signals in the brain to control muscles. They are used to treat a wide variety of conditions, from Parkinson’s disease and loss of bladder control to asthma, chronic obstructive pulmonary disease, or depression.
The new study, led by the University of East Anglia (UK), has found that long-term use of certain types of anticholinergics is linked to an increased risk of dementia, thus confirming the link with long-term use of anticholinergics for depression and also for Parkinson’s disease (such as procyclidine) and loss of bladder control (such as oxybutynin, solifenacin, and tolterodine).
However, the study did not find a relationship between increased risk of dementia and other anticholinergic drugs, such as antihistamines and medications for abdominal cramps.
For their research, the experts used data from the Clinical Practice Research Database, which contains anonymous records for more than 11 million people across the UK.
The data set used included 40,770 patients with dementia aged between 65 and 99 years, who were diagnosed during 2006-2015. Each registry was matched with up to seven people who did not have dementia but were of the same sex and similar age, and the information was followed up for 4-20 years prior to dementia diagnosis.
The researchers used a system called the Anticholinergic Cognitive Burden (ACB) scale to assess the anticholinergic effect of drugs that patients had been prescribed.
An ACB score of 1 meant that a drug was “possibly anticholinergic,” while a score of 2 or 3 meant it was “definitely anticholinergic.” In total, they analyzed more than 27 million recipes.
They found that 35% of dementia patients and 30% of control subjects had received at least one medication with a score of 3 on the ACB scale during that period. The researchers then carried out further analysis to eliminate the effect of factors that could influence the results.
Subsequent analysis revealed that medications with an ACB score of 3 that had been prescribed for depression, Parkinson’s, and loss of bladder control were associated with an increased risk of dementia for up to 20 years “post-exposure.”
However, no such link was found for drugs that scored 1 on the ACB scale, or for respiratory and gastrointestinal drugs that scored 3.
The researchers note that due to limitations in their study design, they cannot tell whether anticholinergics directly cause dementia or not. But, because the link was present even when exposure occurred 15-20 years before dementia was diagnosed, the authors argue that “reverse causality or confusion with early dementia symptoms are less likely explanations. “.
They advise physicians to “remain vigilant regarding the use of anticholinergic drugs” and to consider possible long-term and short-term effects when weighing risks versus benefits. Let’s not forget that dementia affects around 50 million people worldwide, and each year 10 million more find out they have the disease , ultimately depriving them of their ability to remember, think, have a conversation and live off their lives. independently.
Reference: Kathryn Richardson et al. Anticholinergic drugs and risk of dementia: case-control study, BMJ (2018). DOI: 10.1136 / bmj.k1315
