Correlation analysis between serum 8 ⁃ hydroxy deoxyguanosine and malondialdehyde levels and cognitive dysfunction in patients with Parkinson's disease

Objective To explore the relationship between the levels of serum 8 ‑ hydroxy deoxyguanosine (8 ‑ OHdG) and malondialdehyde (MDA) and cognitive dysfunction in patients with Parkinson's disease (PD). Methods From February 2021 to February 2022, 126 patients with PD in The Affiliated Hospital of Xuzhou Medical University were divided into normal cognitive function group (PDN group, n = 41), mild cognitive impairment group (PD‑MCI group, n = 47) and Parkinson's disease dementia group (PDD group, n = 38), and 50 healthy subjects were selected as control group. Hoehn‑Yahr staging was used to evaluate the severity of patients with PD during the "close" period of anti‑PD drugs, and the motor function of patients with PD was evaluated by the Unified Parkinson's Disease Rating Scale Ⅲ (UPDRS Ⅲ). Montreal Cognitive Assessment (MoCA) was used to evaluate the severity of cognitive dysfunction at rest and in the "on" period of anti‑ PD drugs, and the serum 8 ‑ OHdG and MDA of PD patients and controls were collected. Pearson and partial correlation analyses were used to analyze the correlation between the levels of serum 8‑OHdG and MDA and MoCA score in PD patients. Univariate and multivariate Logistic regression analyses were used to analyze the influencing factors of cognitive dysfunction in PD patients. The efficacy analysis of serum 8‑OHdG and MDA levels in predicting the risk of cognitive dysfunction in PD patients was carried out by using receiver operating characteristic curve (ROC curve). Results The results of correlation analysis showed that there was a negative correlation between the MoCA score and the duration (r = ‑ 0.241, P = 0.007), Hoehn‑Yahr staging (r = ‑ 0.333, P = 0.007), 8‑OHdG (r = ‑ 0.310, P = 0.000) and MDA (r = ‑ 0.291, P = 0.004) in PD patients. The results of Logistic regression analysis showed that the elevated levels of 8‑OHdG (OR = 1.335, 95%CI: 1.137-1.568; P = 0.000) and MDA (OR = 2.928, 95%CI: 1.676-5.115; P = 0.000) were risk factors for cognitive dysfunction in PD patients. The results of ROC curve showed the areas under the curve of 8‑OHdG, MDA and their combination in predicting cognitive dysfunction in PD patients were 0.831 (95%CI: 0.761-0.902, P = 0.000), 0.846 (95%CI: 0.775-0.916, P = 0.000) and 0.922 (95%CI: 0.878-0.966, P = 0.000), respectively. Conclusions The detection of 8‑OHdG and MDA in peripheral blood is expected to be a serum marker to evaluate the severity of cognitive dysfunction in patients with PD, and to predict cognitive dysfunction in patients with PD.