Association of serum uric acid level with cognitive function among patients with multiple system atrophy

Oxidative stress is involved in the pathogenesis of multiple system atrophy (MSA) and cognitive impairment. Uric acid has an anti-oxidative effect. Our objective is to clarify the correlations between serum uric acid and cognitive function as well as frontal lobe function in Chinese MSA patients.

All of MSA patients were evaluated using Addenbrooke's Cognitive Examination-Revised (ACE-R), Frontal Assessment Battery (FAB), and Unified MSA Rating Scale (UMSARS). The fasting serum uric acid concentrations of MSA patients were measured.

A total of 89 probable MSA patients with a mean age of 58.6 ± 10.0 years old and disease duration of 2.6 ± 1.5 years were included. Thirty-three patients (37.1%) had global cognitive deficits according to ACE-R. Based on FAB, 35 patients (39.3%) had frontal lobe dysfunction. After adjusting for educational years, patients with cognitive deficits had lower uric acid level than patients without cognitive deficits. Patients with frontal lobe dysfunction had lower uric acid level after adjusting for UMSARS scores. In a forward multiple linear regression, uric acid level and educational years were the variables predicting the ACE-R score (F=36.540, R(2)=0.459, p=0.0001), uric acid accounting for 14% of the total variables. Uric acid was the only variable contributing to the FAB score (F=18.551, R(2)=0.176, p=0.0001).

Our study suggested that low level of serum uric acid was associated with cognitive deficits in MSA. Low uric acid level predicting cognitive decline in MSA needs more studies.