Abstract:Objective: To analyze the changes in levels of serum cystatin C (CysC) and SAA in patients with Parkinson’s disease (PD) and their relationship with cognitive impairment.Methods: Patients who received treatment and physical examination in the hospital from August 2019 to August 2023 were selected as the research subjects, including 150 PD patients as the case group and 90 healthy volunteers as the control group. Cognitive function was assessed using Montreal Cognitive Assessment Scale (MoCA). The general data, serum CysC and SAA levels, and MoCA scores were compared. The levels of CysC and SAA were compared among patients with different Hoehn and Yahr (H-Y) stages. The CysC and SAA levels were compared between the case group and the control group. The correlation of CysC and SAA with H-Y staging and MoCA score was analyzed using Pearson analysis.Results: The levels of CysC and SAA in the case group were higher while the MoCA score was lower than in the control group (P<0.05). CysC and SAA revealed the control group < the early PD group < the middle and late PD group, while MoCA score revealed the control group > the early PD group > the middle and late PD group (P<0.05). CysC and SAA levels revealed the control group < normal cognition group < cognitive impairment group (P<0.05). The levels of serum CysC and SAA in PD patients were positively correlated with H-Y staging (r=0.610, 0.565, P<0.05), and were negatively associated with MoCA score (r=-0.352, -0.533, P<0.05).Conclusion: The levels of CysC and SAA in the serum of PD patients are increased. With the increase of H-Y stage, the levels of CysC and SAA rose while the MoCA score decreased. The levels of serum CysC and SAA in PD patients were positively correlated with H-Y staging and negatively correlated with MoCA score.