Easy as ACB: Drug side effect linked with increased health risks for over 65s
24 June 2011
New research from the Medical Research Council Cognitive Function and Ageing Studies (CFAS) project shows that a side effect of many commonly used drugs appears to increase the risks of both cognitive brain impairment and death in older people.
This study, led by the University of East Anglia (UEA), is the first systematic investigation into the long term health impacts of ‘anticholinergic activity’ – a known potential side effect of many prescription and over the counter drugs. Anticholinergic activity affects the brain by blocking the action of a key brain chemical called acetylcholine. The two year study was launched as part of the drive to find ways of reducing risk factors for dementia, which affects 820,000 people in the UK. More than 13,000 men and women aged 65 and over from across the UK were involved in the study, half of whom were using a medication with potential anticholinergic properties.
Medicines with some degree of anticholinergic effect are wide-ranging and many are frequently taken by older people. The groups with the greatest impact include anti-depressants, tranquilisers, bladder medication and anti-histamines (used as anti-inflammatory drugs). In the study, each drug taken by the participants was given a ranking based on the strength of its anticholinergic activity, or AntiCholinergic Burden (ACB) – 0 for no effect, 1 for mild effect, 2 for moderate effect and 3 for severe effect. The researchers found that twenty per cent of participants taking drugs with a total ACB score of four or more had died by the end of the two-year study, compared with only seven per cent of those taking no anticholinergic drugs. This is the first time a link between anticholinergics and mortality has been shown. Additionally, participants taking drugs with a combined ACB of five or more scored more than four per cent lower in a cognitive function test than those taking no anticholinergic medications.
Co-author Professor Carol Brayne, principal investigator of the Medical Research Council CFAS project at the University of Cambridge, said:
“It is important to scrutinise medications given to older people very carefully to try to minimise harm as well as gain the desired benefit. The admirable wish to give the best possible treatment for individual conditions has to be balanced against the fact that in many older people with multiple conditions, this will lead to accumulated risk.”
Lead author Dr Chris Fox, clinical senior lecturer at Norwich Medical School, UEA, said:
“Our results show a potentially serious effect on mortality. Clinicians should conduct regular reviews of the medication taken by their older patients, both prescribed and over the counter, and wherever possible avoid prescribing multiple drugs with anticholinergic effects.”
Professor Chris Kennard, chairman of the MRC’s Neuroscience and Mental Health Board, which funded the research, said:
“The Medical Research Council invests in cohort studies like CFAS because they provide vital clinical information through observation. Such projects require long-term funding to fulfil their potential and, having supported cohort studies for well over half a century, the MRC’s commitment has made the UK an international leader in this field.”
CFAS is a large, multi-centre initiative launched over 20 years ago to examine health and cognitive function in older adults. Visit www.cfas.ac.uk for more details. For this study, the UEA researchers worked in collaboration with colleagues at University of Cambridge, Indiana University and NHS clinicians. The ACB scale was developed by scientists at the Regenstrief Institute in Indianapolis, US, supported by scientists from Norwich Medical School at UEA, and the NHS. Visit www.indydiscoverynetwork.org/AnticholinergicCognitiveBurdenScale.html for more details.
‘Anticholinergic medication use and cognitive impairment in the older population: The Medical Research Council Cognitive Function and Ageing Study (CFAS)’ by C. Fox, K. Richardson, I. Maidment, G. Savva, F. Matthews, D. Smithard, S. Coulton, C. Katona, M. Boustani, and C. Brayne is published online by the Journal of the American Geriatrics Society.
