Anticholinergic burden in adults with learning disabilities


Anticholinergic burden is the cumulative effect of using multiple medications with anticholinergic effects. Whilst many medicines have intended therapeutic anticholinergic effects, such as antiparkinsonians, many have unintended anticholinergic side-effects, such as antipsychotics. Additive effects can be harmful and often include many factors associated with learning disabilities, such as cognitive impairment and constipation, which can be difficult to detect leading to further health problems for these individuals (diagnostic overshadowing). There is increasing evidence of the adverse effects anticholinergic burden may have on a patient from increased fall risk to all-cause mortality. However, there is limited available evidence regarding how adults with learning disabilities are affected by anticholinergic burden, especially at younger ages. We aimed to address this.

What we did

We used the Primary Care Intellectual Disabilities Register of NHS Greater Glasgow & Clyde to identify a representative population of adults with learning disabilities (aged 17 – 94). The n=4 305 adults with learning disabilities were matched to general population controls (n=12 915) on age, sex and neighbourhood area. We obtained permission to access administrative health data linking information from pharmacists and doctors.

What we found

More adults with learning disabilities were prescribed (any) anticholinergic medications compared to the general population (57.9%, 48.3% respectively). This was consistently true for every risk level of medicine, but for those medicines with a ‘very strong’ anticholinergic risk, adults with learning disabilities were prescribed more than twice the amount compared to controls (33.2%, 16.4% respectively). Summated total anticholinergic burden scores showed that compared 48.5% of adults with learning disabilities had very high total burden compared to 35.4% of controls, this was true for both sexes, and greater for men. As expected, total anticholinergic burden increased with age, but to a lesser extent for the learning disabilities group, who experienced very high anticholinergic burden at all ages. Group differences were greatest at younger ages; for those aged 17-24 years old, the adults with learning disabilities were three times more likely than controls to experience very high anticholinergic burden.
There were differences between the learning disabilities and control groups in all neighbourhood areas, with the extent of the difference increasing with increasing affluence of neighbourhood. Irrespective of sex, age or neighbourhood area, adults with learning disabilities are at a higher risk of anticholinergic burden than controls. Within the learning disabilities group alone, very high anticholinergic burden was greatest for women and those over the age of 55 years.

What these findings mean

Adults with learning disabilities are at a higher risk of anticholinergic burden than controls, especially young adults. This is a novel and important finding which highlights the large prevalence of very high anticholinergic burden in this population. This anticholinergic burden increases the likelihood of unintended adverse effects caused by medication, in an already vulnerable cohort. This could be addressed by patient medication reviews with consideration to the anticholinergic burden induced by multiple drugs, as well as other alternative interventions such as psychosocial/ behavioural interventions for challenging behaviours and sleep problems. Careful prescribing and regular multidisciplinary medication reviews could minimize the adverse effects experienced by those patients with very high anticholinergic burden.

For more information about this research, please contact Dr Laura Ward

Page updated 20 January 2020