OBJECTIVES

: Recent studies raised concerns about the potential link between anticholinergic medication use and an increased risk of cognitive impairment. However, whether taking anticholinergic medications was associated with a long-term and irreversible cognitive impairment such as dementia remains unknown. The purpose of this study was to evaluate the association between anticholinergic medication use and the risk of dementia among patients with Parkinson’s disease.

METHODS

: We conducted a retrospective cohort study with a new anticholinergic drug user design using an 11-years (2001-2011) National Health Insurance Research Database (NHIRD) in Taiwan. Patients were included if they were diagnosed with Parkinson’s disease between January 1, 2002 and December 31, 2004. The expose to anticholinergic medications was categorized using the Anticholinergic Cognitive Burden Scale (low vs. high) and the cumulative doses of anticholinergic medications were measured using the Cumulative Minimum Doses (CMD). The outcome was the diagnosis of dementia during the follow-up period until the end of the data period. Cox-proportional hazard models were used to compare hazard ratios between the groups and its association with the risk of dementia after adjusted confounders.

RESULTS

: Our study population included 1,232 patients with Parkinson’s disease. Among them, 43.7% were users with medications of a high anticholinergic cognitive burden. After adjusted for confounders, patients with a high cumulative dose of anticholinergic medications (> 1,095 CMD) were found to be associated with a higher risk of dementia when compared to patients with a low cumulative dose of anticholinergic medications (≤ 90 CMD) (Hazard Ratio: 3.04, 95% CI: 1.34-6.92).

CONCLUSIONS

: Patients with a high cumulative dose of anticholinergic medications had a higher risk of being diagnosed with dementia. Physician's prescribing anticholinergic medications to patients with Parkinson’s disease needed a careful consideration to avoid the risk of dementia.