Assessment and comparison of anticholinergic exposure in older adults at a Basic Health Unit in Porto Alegre

OBJECTIVES: To estimate the anticholinergic burden in geriatric patients using two scales and to assess the degree of agreement between them. METHODS: Data from an observational study conducted in a primary health care service were used. Anticholinergic burden was assessed using the Belgian Scale Muscarinic Acetylcholinergic Receptor ANTagonist Exposure Scale and the Brazilian Scale of Medicines with Anticholinergic Activity. The cumulative anticholinergic burden score was classified using a categorical approach: Brazilian scale (0: none; 1 - 2: low; ≥ 3: high) and Belgian scale (0: none; 0.5 - 1.5: low; ≥ 2: high). The degree of agreement between the two instruments was obtained through Cohen's kappa coefficient. RESULTS: A total of 374 older people were included, most of them female and aged between 60 and 69 years. At least one potentially inappropriate drug with anticholinergic activity was used by 60.70% of patients according to the Brazilian scale and 32.89% by the Belgian scale. On average, 20.85% were under high anticholinergic exposure. Overall, on both scales, the most commonly recurrent medications were those indicated for the treatment of psychiatric disorders. Agreement between the scales was moderate (Kappa = 0.43). CONCLUSIONS: A high percentage of older adults was exposed to drugs with an anticholinergic burden, posing risks to health and quality of life. Consensus is needed on how anticholinergic burden is calculated by these scores, as well as standardization of the list of included drugs.