Impact of multiple low-level anticholinergic medications on anticholinergic load of community-dwelling elderly with and without dementia.

BACKGROUND

Elderly people, particularly those with dementia, are sensitive to adverse anticholinergic drug effects. This study examines the prevalence of anticholinergic medication, and anticholinergic load and its predictors, in community-dwelling elderly patients (aged 75 years and older) in Australia.

METHODS

A research nurse visited the home of each participant (n = 1,044), compiled a list of current medications, and assessed participants' cognitive status using a subsection of the revised Cambridge Examination for Mental Disorders of the Elderly (CAMCOG-R). Anticholinergic load was determined for each patient using the Anticholinergic Drug Scale (ADS).

RESULTS

Multivariate analysis identified several patient factors that were associated with higher anticholinergic burden, including polypharmacy (i.e. taking five or more medications) (p < 0.001), increasing age (p = 0.018), CAMCOG-R dementia (p = 0.003), depression (p = 0.003), and lower physical quality of life (p < 0.001). The dementia group (n = 86) took a significantly higher number of medications (4.6 vs. 3.9; p = 0.04), and had a significantly higher anticholinergic load (1.5 vs. 0.8; p = 0.002) than those without dementia (n = 958). Approximately 60% of the dementia group and 40% of the non-dementia group were receiving at least one anticholinergic drug. This difference was due to the higher proportion of dementia patients taking level 1 (potentially anticholinergic) (p = 0.002) and level 3 (markedly anticholinergic) (p = 0.005) drugs.

CONCLUSIONS

There is considerable scope for the improvement of prescribing practices in the elderly, and particularly those with dementia. Importantly, level 1 anticholinergics have been identified as major contributors to the anticholinergic load in people with dementia. Longitudinal studies are required to determine the effects of increased and decreased anticholinergic load on cognitive function and other clinical outcomes for people with dementia.