Anticholinergic burden in community-dwelling older adults: prevalence, associated factors, and agreement between measurement scales

Aim Assessing cumulative anticholinergic exposure is essential in geriatric pharmacotherapy and medication safety. The present study aimed to provide real-world evidence on this issue in community-dwelling older adults. The objectives were: (i) to determine the prevalence of anticholinergic medication use; (ii) to analyze factors related to this use; and (iii) to assess the agreement between the scales applied. Methods This multicenter cross-sectional study included 365 participants aged 65 years or older, recruited from nine urban primary healthcare centers in the city of Málaga (Andalusia, Spain), using stratified random sampling. Anticholinergic burden was calculated for all regular medications taken by participants through the application of five scales: the Anticholinergic Cognitive Burden Scale (ACB), Anticholinergic Risk Scale (ARS), Anticholinergic Drug Scale (ADS), Anticholinergic Burden Classification (ABC), and Drug Burden Index (DBI). Factors associated with the rate of anticholinergic medication use were examined using a multivariable quasi-Poisson regression model with the total number of medications included as an offset. Pairwise agreement for any anticholinergic exposure between scales was assessed using contingency tables and Cohen’s kappa coefficient. Results Overall, 74.2% of participants were taking one or more medications with anticholinergic properties according to at least one scale. However, relevant differences were observed across the assessment instruments. Only moderate agreement was found between ADS and DBI (κ = 0.48) and between ADS and ACB (κ = 0.44); all other pairwise comparisons showed weak or very weak agreement. Anxiolytics/hypnotics (mainly benzodiazepines), antidepressants, urological antispasmodics, antihistamines, opioid analgesics, antipsychotics, and antiepileptic drugs were the therapeutic classes most frequently contributing to anticholinergic exposure. The rate of anticholinergic medication use was 30.5% higher in patients with any mental health condition, mainly anxiety and/or depression, than in those without such diagnoses (Rate Ratio = 1.305, 95% CI: 1.127–1.511). Conclusion This study found a high prevalence of exposure to medications with anticholinergic activity among community-dwelling older adults. Although more than 50 medications were identified by the applied tools, benzodiazepines represented the therapeutic class most frequently contributing to patients’ anticholinergic burden. Clinicians should be familiar with the available tools to identify high-risk medications, consider safer alternatives, and support more appropriate prescribing.