Polypharmacy Associated with Cognitive Decline in Newly Diagnosed Parkinson's Disease: A Cross-Sectional Study

AIMS: Polypharmacy is well known to affect cognitive function in community-dwelling older adults. However, the effect of polypharmacy on cognitive function in patients with newly diagnosed Parkinson's disease remains unknown. Here, we evaluated the association between polypharmacy and cognitive function in patients with newly diagnosed Parkinson's disease. METHODS: This cross-sectional study enrolled 131 consecutive hospitalized patients with newly diagnosed Parkinson's disease. Cognitive function was evaluated with the Mini-Mental State Examination and analyzed between groups of patients with or without polypharmacy. Comparisons were adjusted for confounders by performing inverse probability weighting with propensity scores. RESULTS: After inverse probability weighting, patients in the polypharmacy group had a significantly lower Mini-Mental State Examination score than patients in the nonpolypharmacy group (26.2 vs. 27.7, p = 0.001). CONCLUSION: Polypharmacy was associated with cognitive decline in patients with newly diagnosed Parkinson's disease. This finding suggests that medication reduction might serve as a promising intervention to prevent the development of dementia in patients with early Parkinson's disease. Further prospective studies are needed to determine whether medication reduction improves cognitive function in patients with newly diagnosed Parkinson's disease.