Anticholinergic Burden and Its Association with Hospitalisation Risk and Causes of Admission in Older Adults with Mild Cognitive Impairment or Dementia.

Background: Older adults with cognitive impairment are vulnerable to the adverse effects of cumulative use of medications with anticholinergic properties. However, existing research on hospitalisation risk in this population remains limited and often lacks focus on the specific causes of admission. This study aims to investigate the role of anticholinergic burden and its association with hospitalisation risk and reasons for admission among older adults with mild cognitive impairment or dementia. Methods: This retrospective study included older adults with mild cognitive impairment or dementia attending the memory clinic between January to December 2022. Collected data from the electronic medical records includes sociodemographic information, comorbidities, cognitive and functional assessment, neuropsychiatric symptoms, and medication history. Anticholinergic burden was assessed using the Anticholinergic Cognitive Burden (ACB) score. Cox proportional hazard analysis was performed to assess the association between ACB scores and hospitalisation risk. The underlying causes of hospital admissions were compared across the different ACB score groups. Results: A total of 657 older adults were included in the analysis, with a mean age of 80.66 (SD 7.39) years. Anticholinergic medication use was seen in 35.5%, with a mean ACB score of 0.8 (SD 1.3). Higher ACB scores were associated with nursing home residency, presence of neuropsychiatric symptom, poorer cognitive and physical function, and a greater number of prescribed medications compared to those with no anticholinergic burden. Older adults with ACB scores of 1-2 had an increased risk of hospitalisation (Hazard Ratio(HR)=1.84,95% CI:1.17-2.90) in univariate analysis, but this association was diminished after adjusting for confounders. The most common reasons for hospital admission were pneumonia (5.7%), acute kidney injury (3.8%), delirium (2.6%) and falls (2.6%). Notably, individuals hospitalised for serious adverse cardiovascular events or infected pressure ulcers had significantly higher ACB scores. Conclusion: One-third of older adults with mild cognitive impairment or dementia use anticholinergic medications, potentially worsening health outcomes. These findings underscore the importance of regular medication review and deprescribing strategies to minimise anticholinergic burden in this vulnerable population.