Cohort study compares homocysteine and uric acid levels in Parkinson's disease-related and post-stroke cognitive impairment.

To compare homocysteine (Hcy) and uric acid (UA) levels between patients with Parkinson’s disease with cognitive impairment (PD-CI) and those with post-stroke cognitive impairment (PS-CI), and to analyze the correlation of these biomarkers with cognitive function and their heterogeneity across different disease types. Patients diagnosed with cognitive impairment who were admitted to the Department of Neurology at Yangjiang Hospital of Traditional Chinese Medicine between January 2025 and December 2025 were included (60 PD-CI; 60 PS-CI). Blood Hcy and UA levels were uniformly measured, and cognitive function was assessed using the Mini-Mental State Examination (MMSE). Covariance analysis compared biomarker level differences between groups. Spearman correlation analysis and multivariate linear regression models with interaction terms explored the relationship between biomarkers and MMSE scores. Binary logistic regression identified factors independently associated with disease type. After adjusting for confounding factors, the PD-CI group exhibited significantly higher Hcy levels (adjusted mean difference: 2.55 μmol/L, 95% CI: 0.23–4.87, p = 0.032), while UA levels were significantly lower (adjusted mean difference: −34.66 μmol/L, 95% CI: −63.87 to −5.46, p = 0.020). In the overall sample, Hcy negatively correlated with MMSE (r = −0.309, p = 0.001). This association was numerically stronger in the PD-CI group (r = −0.456, p  Patients with PD-CI and PS-CI exhibit distinct metabolic profiles, with the PD-CI group characterized by elevated Hcy and low UA levels. Although elevated Hcy is a common factor associated with cognitive impairment in both conditions, UA levels in this cohort were independently associated with PD-CI (relative to PS-CI), not with MMSE scores. These findings suggest potential differences in metabolic profiles and may offer new insights for clinical differential diagnosis. As an exploratory cross-sectional analysis, these findings require validation in prospective studies.