Drugs Contributing to Anticholinergic Burden and Risk of Fall or Fall-Related Injury among Older Adults with Mild Cognitive Impairment, Dementia and Multiple Chronic Conditions: A Retrospective Cohort Study

Background: It is not known whether drugs with different anticholinergic ratings contribute proportionately to overall anticholinergic score. Objectives: Our objective was to assess the risk of falls or fall-related injuries as a function of the overall anticholinergic score resulting from drugs with different anticholinergic ratings among people with impaired cognition. Methods: This was a retrospective cohort study of adults aged ≥ 65 years with mild cognitive impairment (MCI) or dementia and two or more additional chronic conditions (N = 10,698) in an integrated delivery system. Electronic health record data, including pharmacy fills and diagnosis claims, were used to assess anticholinergic medication use, quantified using the anticholinergic cognitive burden (ACB) scale, falls and fall-related injuries. Results: During a median follow-up of 366 days, 63% of the cohort used one or more ACB drug; 2015 (18.8%) people experienced a fall or fall-related injury. Among patients with a daily ACB score of 5, the greatest increase in risk of falls or fall-related injuries was seen when level 2 and level 3 drugs were used in combination [hazard ratio (HR) 2.06; 95% confidence interval (CI) 1.51–2.83]. Multiple ACB level 1 drugs taken together also increased the hazard of a fall or fall-related injury (HR 1.16; 95% CI 1.03–1.32). The risk of fall or fall-related injury as a function of exposure to ACB level 2 drugs (HR 1.56; 95% CI 1.16–2.10) was higher than that for ACB level 1 or 3 drugs. Conclusions: The same daily ACB score was associated with a different degree of risk, depending on the ACB ratings of the individual drugs comprising the score. Combinations of level 2 and level 3 drugs had the greatest risk of fall or fall-related injury relative to other individuals with the same daily ACB score. Low-potency anticholinergic drugs taken together modestly increased the hazard of a fall or fall-related injury.