Risk factors for dementia in Parkinson's Disease - the overuse of anticholinergic drugs

Aim of the study: To determine the risk factors for dementia in a group of patients with Parkinson's Disease (PD), especially the effect of the anticholinergic burden assessed according to the Anticholinergic Cognitive Burden scale (ACB) and the CRIDECO Anticholinergic Load Scale (CALS).

Clinical rationale for the study: To provide information about factors associated with Parkinson's Disease dementia (PDD), especially the anticholinergic burden and testing the effect of both scales in an assessment of the anticholinergic burden in this group of patients.

Material and methods: A retrospective and cross-sectional analysis of medical records of patients with Parkinson's Disease admitted to the Neurology Department of the Medical University of Silesia, Katowice, Poland between 2019 and 2021 was performed. We found 418 patients with a diagnosis of PD, but 80 were excluded due to lack of a cognitive function assessment. Based on MMSE score, the remaining 338 patients were divided into two groups of patients with, and without, PDD. Next, demographic and clinical data was collected. The anticholinergic burden was assessed using the ACB and the CALS scales. According to the authors of these scales, : if a scale score is of three or more points, this should be considered as a significant anticholinergic burden. Multiple logistic regression with backward elimination was used to assess factors significantly related to the presence of dementia, and two different models were used for both scales assessing the anticholinergic burden.

Results: 62 (18.3%) patients were diagnosed with PDD. Overall significant anticholinergic burden (≥ 3 points) was found in 31.95% of patients using CALS and in 18.93% using ACB. Anticholinergic burden was higher in patients with dementia (CALS 50 vs. 27.90%, p < 0.001, ACB 43.5 vs. 13.41%, p < 0.001). According to both models, the factors significantly related to dementia were: age (ACB OR 1,114 (1.062-1.170), p < 0.001, CALS OR 1.123 (1.070-1.178), p < 0.001), significant anticholinergic burden (ACB OR 3.433 (1.746-6.750), p < 0.001, CALS OR 2.166 (1.157-4.055), p = 0.016) disease severity in the Hoehn-Yahr scale (ACB OR 1.752 (1.197-2.565), p = 0.004, CALS OR 1.831 (1.256-2.670), p = 0.002) and atrial fibrillation (ACB OR 5.593 (1.417-22.083), p = 0.014, CALS OR 5.159 (1.314-20.254), p = 0.016).

Conclusions and clinical implications: The anticholinergic burden is larger in PDD patients compared to PD patients without dementia. CALS or ACB scales are helpful in this risk assessment and might be crucial to avoid the development of PDD, especially in older PD patients with multimorbidities.