Serum uric acid levels in patients with Parkinson's disease: A meta-analysis.
BACKGROUND
Lower serum uric acid (UA) levels have been reported as a risk factor in Parkinson's disease (PD). However, the results have been inconsistent so far.


OBJECTIVE
The aim of the present study was to clarify the potential relationship of uric acid with PD.


METHODS
Comprehensive electronic search in pubmed, web of science, and the Cochrane Library database to find original articles about the association between PD and serum uric acid levels published before Dec 2015. Literature quality assessment was performed with the Newcastle-Ottawa Scale. Random-effects model was used to estimate the standardized mean differences (SMDs) with 95% confidence intervals (CIs). Heterogeneity across studies was assessed using I2 and H2 statistics. Sensitivity analyses to assess the influence of individual studies on the pooled estimate. Publication bias was investigated using funnel plots and Egger's regression test. Analyses were performed by using Review Manager 5.3 and Stata 11.0.


RESULTS
Thirteen studies with a total of 4646 participants (2379 PD patients and 2267 controls) were included in this meta-analysis. The current results showed that the serum UA levels in PD patients were significantly lower compared to sex and age-matched healthy controls (SMD: -0.49, 95% CI: [-0.67, -0.30], Z = 5.20, P < 0.001) and these results showed no geographic regional (Asia: SMD = -0.65, 95% CI [-0.84, -0.46], Z = 6.75, p <0.001; Non-Asia: SMD = -0.25, 95% CI [-0.43, -0.07], Z = 2.70, p = 0.007) and sex differences (women: SMD = -0.53, 95% CI [-0.70, -0.35], z = 5.98, p <0.001; men: SMD = -0.66, 95% CI [-0.87, -0.44], z = 6.03, p <0.001). Serum UA levels in middle-late stage PD patients with higher H&Y scales were significantly lower than early stage PD patients with lower H&Y scales (SMD = 0.63, 95% CI [0.36,0.89], z = 4.64, p <0.001).


CONCLUSIONS
Our study showed that the serum UA levels are significantly lower in PD and the level is further decreased as the disease progresses. Thus it might be a potential biomarker to indicate the risk and progression of PD.
Department of Anatomy, Guizhou Medical University, Guiyang, China.
Min
M
Wen
Department of Biology, Guizhou Medical University, Guiyang, China.
Bo
B
Zhou
Department of Anatomy, Guizhou Medical University, Guiyang, China.
Yun-Hua
YH
Chen
Department of Neurology, BaiYun Hospital, Guizhou Medical University, Guiyang, China.
Zhao-Lei
ZL
Ma
Department of Anatomy, Guizhou Medical University, Guiyang, China.
Yun
Y
Gou
Department of Biology, Guizhou Medical University, Guiyang, China.
Chun-Lin
CL
Zhang
Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, P. R. China; Key Laboratory of Medical Molecular Biology, Guizhou Medical University, Guizhou Province, Guiyang, P. R. China.
Wen-Feng
WF
Yu
Department of Neurology, Affiliated Hospital, Guizhou Medical University, Guiyang, China.
Ling
L
Jiao
D006801:Humans; D010300:Parkinson Disease / Q000097:blood*; D014527:Uric Acid / Q000097:blood*
D014527:Uric Acid