Anticholinergic drug use, serum anticholinergic activity, and adverse drug events among older people: a population-based study

Abstract

Background: The serum anticholinergic activity (SAA) assay has been used to quantify patients' anticholinergic load. In addition, several ranked lists of anticholinergic drugs have been developed to assess anticholinergic drug burden.

Objective: This study investigated whether SAA assay results and scores from three ranked lists of anticholinergic drugs (Carnahan's Anticholinergic Drug Scale, Rudolph's Anticholinergic Risk Scale, and Chew's list) are associated with anticholinergic adverse drug events (ADEs) in older people.

Methods: We analyzed data from participants in the population-based Geriatric Multidisciplinary Good Care of the Elderly Study in Kuopio, Finland (n = 621). Demographic, diagnostic, and drug use data were collected during standardized interviews and verified from medical records. Vision, functional capacity, cognition, and mood were assessed using validated techniques. The SAA was measured from blood samples.

Results: The SAA was not associated with anticholinergic ADEs. Anticholinergic drug burden computed using each of the three lists was inversely associated with short-distance vision (p < 0.01), activities of daily living (p < 0.05), and instrumental activities of daily living (p < 0.05) in persons with and without dementia. Furthermore, poorer Mini Mental State Examination and poorer Geriatric Depression Scale scores were associated with the anticholinergic drug burden in persons without dementia (p < 0.05-p < 0.001). The association between anticholinergic drug burden and ADEs was strongest when using the lists developed by Carnahan and Chew.

Conclusions: Scores obtained from ranked lists of anticholinergic drugs were associated with clinically significant anticholinergic ADEs but the SAA was not. This finding supports the usefulness of these lists to help identify patients at risk of anticholinergic ADEs in clinical practice.