Characteristics of Parkinson's Disease in Patients with and without Cognitive Impairment

Background: Characterizing patients with Parkinson's disease (PD) and cognitive impairment is important toward understanding their natural history. Objective: Understand clinical, treatment, and cost characteristics of patients with PD pre- and post-cognitive impairment (memory loss/mild cognitive impairment/dementia or dementia treatment) recognition. Methods: 2,711 patients with PD newly diagnosed with cognitive impairment (index) were identified using administrative claims data. They were matched (1:1) on age and gender to patients with PD and no cognitive impairment (controls). These two cohorts were compared on patient characteristics, healthcare resource utilization, and total median costs for 3 years pre-and post-index using Chi-square tests, t-tests, and Wilcoxon rank-sum tests. Logistic regression was used to identify factors predicting cognitive impairment. Results: Comorbidity indices for patients with cognitive impairment increased during the 6-year study period, especially after the index. Enrollment in Medicare Advantage Prescription Drug plans vs. commercial (OR = 1.60), dual Medicare/Medicaid eligibility (OR = 1.36), cerebrovascular disease (OR = 1.24), and PD medication use (OR = 1.46) were associated with a new cognitive impairment diagnosis (all p < 0.05). A greater proportion of patients with cognitive impairment had hospitalizations and emergency department visits and higher median total healthcare costs than controls for each year pre- and post-index. Conclusion: In patients with PD newly diagnosed with cognitive impairment, comorbidity burden, hospitalizations, emergency department visits, and total costs peaked 1-year pre- and post-identification. These data coupled with recommendations for annual screening for cognitive impairment in PD support the early diagnosis and management of cognitive impairment in order to optimize care for patients and their caregivers.