Anticholinergic bladder drugs and associations with dementia risk.

Dementia is a very common cause of disability, dependency, and death among older people worldwide. It affects an average of 50 million people in the world, and there are nearly 10 million new cases every year.

Previous studies have shown that individuals who take a certain class of medication, known as anticholinergics (pronounced “antee-ko-lin-urh-jiks”), for a long period of time, have a higher risk of developing memory decline and dementia. A strong link has been found in those who used the sub-class of anticholinergic drugs that are used to treat a bladder symptom, known as overactive bladder, in older people. This is important because these drugs are commonly used, with over 274 million prescriptions issued for these in England and Wales in 2019. Whilst anticholinergics are the first-line drug treatment for overactive bladder, a few small-scale research studies have suggested that there may be differences between the drugs in the extent to which they affect individuals’ memory, and risk of dementia. There is a need for a large-scale study to find out if there are indeed differences in risk of dementia associated with the different drugs. The results would help doctors to know if some anticholinergics for treating overactive bladder are safer than others when making prescribing decisions. 

To address this important evidence and research gap, the proposed research aims to assess the link between the different anticholinergic drugs used to treat overactive bladder, and the risk of dementia. We will use a large database of computerised primary care records to identify people with dementia. Each person with dementia will be matched with up to five people of a similar age, sex and registered in the same general practice, who do not have dementia. Individuals with dementia and their matched non-dementia individuals, will be compared and assessed in terms of their differences in prior use of different anticholinergics used to treat overactive bladder. We will also assess use of a different non-anticholinergic medicine for overactive bladder called mirabegron, and this will be used to see whether there is a higher risk in the anticholinergic medicines compared with a non-anticholinergic medicine in treatment of this condition. In doing this, we will be able to assess the risk of dementia associated with the different anticholinergics prescribed for overactive bladder up to 20 years before the diagnosis of dementia.

Findings from this research will help answer an important question about the safety of different anticholinergic drugs and risk of dementia. The results may change the advice that doctors are given about prescribing these drugs, particularly if some are found to be safer than others and this could help reduce dementia risk.

Amount awarded: £45322.46