Research finds common anticholinergic drugs increase risk of mortality in people with dementia

The research has been published in Aging & Mental Health.

Anticholinergics are a type of medication that blocks the action of a neurotransmitter, a chemical messenger in the brain, called acetylcholine. They are commonly used to treat a variety of conditions, including urinary incontinence, allergies and depression.

In 2015, over 47 million people worldwide were living with dementia and this figure is expected to increase to 66 million in 2030 and 115 million in 2050. In Northern Ireland, it is estimated that there are currently 19,000 people living with dementia, a number which could potentially increase to 60,000 by 2050. People with dementia are more likely to be taking medications for a range of diseases and/or illnesses than people without dementia, moreover, some of these comorbidity medications are likely to have anticholinergic properties.

Dr Alan McMichael, Researcher from the Centre for Public Health at Queen’s University and first author on the paper, said: “The aim of this study was to examine the risk of mortality associated with anticholinergic use among those with dementia. We looked specifically at people in Northern Ireland as this had never been studied before.

“We already know there is a link between anticholinergic use and a higher risk of developing dementia or cognitive impairment, but little is known about the link between anticholinergic use and whether they influence mortality rates among people with dementia.”

To conduct the study, the researchers looked at data from the Enhanced Prescribing database for 25,418 people who were prescribed at least one dementia management medication between 2010 and 2016. Information was also extracted on the number of times each available anticholinergic drug was prescribed between 2010 and 2016, allowing the calculation of an overall anticholinergic burden (which refers to the cumulative effect of taking one or more medications with anticholinergic activity). Statistical models were then used to estimate the effects of anticholinergic medication on survival, whilst multilevel model regression determined what demographic characteristics influence overall anticholinergic burden.

The study found that higher anticholinergic burden in people with dementia was associated with significantly higher mortality rates in comparison to people with dementia who had no anticholinergic burden. The researchers found of the 25,418 people with dementia, only 15 per cent had no anticholinergic burden. Diazepam (42 per cent) and risperidone (18 per cent) were found to be the two most commonly prescribed drugs and respiratory and urological drugs in particular significantly increased mortality rates among people with dementia.

The results also found people with dementia living in areas with low levels of deprivation had a significantly lower anticholinergic burden, while those living in rural areas had a higher anticholinergic burden compared to those living in urban areas.

Dr Bernadette McGuinness, Researcher from the Centre for Public Health at Queen’s, Consultant Geriatrician at the Belfast Health and Social Care Trust and senior author on the paper, said: “Our study has shown that drugs with a high anticholinergic burden increase mortality in people with dementia. These findings are especially important for the people of Northern Ireland but, are also highly relevant for people with dementia, their families, carers and healthcare professionals world-wide.

“We hope this discovery will pave the way for better understanding of the effect of anticholinergic drugs and leads to better treatment options for people with dementia. Further research should address the unfavorable prognosis of people living with dementia in highly deprived areas to improve their life expectancy.”

Seamus McErlean, Commissioning Lead for Dementia, Health and Social Care Board, said: “This is an important piece of research, the findings of which significantly enhance our understanding of pharmaceutical regimes in dementia care. The lessons from it need to be disseminated and acted upon while at the same time continuing to promote and support further research into the possible causes of the condition, a cure and best care practice in dementia care.”

The study was funded by Atlantic Philanthropies, The Executive Office and The Department of Health as part of a wider Dementia eHealth and Data Analytics Pathfinder Programme. The Health and Social Care Board (HSCB) has been tasked with delivering this programme which has separate workstreams, five focusing on eHealth and three on Data Analytics.

This Programme has two related strands – one of which is focused on building the capacity to collect and use dementia data to improve the planning and commissioning of efficient, effective and value for money dementia services, and to create a platform that can be utilised to enable data driven care-planning solutions across the health and social care system.

This Queen's study is one of 14 studies being commissioned using dementia data. Data analytics research into dementia has the potential to rapidly improve the understanding of the progression of dementia and help assess the effectiveness of interventions and treatments in Northern Ireland.