Serum uric acid levels in patients with Parkinson’s disease: A meta-analysis

PLOS ONE, Dec 2019

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. Objectives 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.

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Serum uric acid levels in patients with Parkinson’s disease: A meta-analysis

March Serum uric acid levels in patients with Parkinson's disease: A meta-analysis Min Wen 0 1 Bo Zhou 0 Yun-Hua Chen 0 1 Zhao-Lei Ma 0 Yun Gou 0 1 Chun-Lin Zhang 0 Wen- Feng Yu 0 Ling Jiao 0 0 Editor: Gotthard Kunze, Leibniz-Institut fur Pflanzengenetik und Kulturpflanzenforschung Gatersleben , GERMANY 1 Department of Anatomy, Guizhou Medical University , Guiyang , China , 2 Department of Biology, Guizhou Medical University , Guiyang , China , 3 Department of Neurology, BaiYun Hospital, Guizhou Medical University , Guiyang , China , 4 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 , 5 Department of Neurology, Affiliated Hospital, Guizhou Medical University , Guiyang , China 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, a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This study was supported by the Natural Science Foundation of Guizhou Province of China (LG [2012]021 and LG[2011]023). Competing interests: The authors have declared that no competing interests exist. Background Objectives Methods −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. 1 Introduction Parkinson's disease (PD) is the second most common neurodegenerative disease that affects approximately 1±2% of the population over 60 years[ 1 ]. PD is characterized by an extensive and progressive loss of dopaminergic neurons in the substantia nigra pars compacta[2]. The cause and pathogenesis resulting from the loss of selective dopamine neurons in PD remain elusive. But increasing evidence suggests that an oxidative stress plays an important role in the degeneration of dopaminergic neurons in PD[ 3 ]. Consequently, research efforts have been directed towards understanding the pathological role of oxidative stress in the pathogenesis and in the hope of developing more effective therapy approaches for the treatment of PD[ 4 ]. Uric acid (UA), one of the end products of purine metabolism is a natural antioxidant in blood and brain tissue, which has neuroprotective effects on PD by effectively scavenging oxygen radicals and reactive nitrogen[5±6]. Numerous large prospective studies have shown that the high levels of serum or plasma urate reduced the risk of PD [7±8]. Recently, the association between serum urate levels and PD has gained intensive interests, but results of these studies have been inconsistent. Some studies have shown a clear trend of lower serum urate levels in PD and subgroups based on sex [9±17], while others showed no significant variation of lower serum urate levels in PD [18±23]. Our previous studies showed that the serum UA levels in PD patients were significantly lower than sex and age-matched healthy controls and the UA concentrations were decreased with the deterioration of the illness[ 24 ]. To evaluate the potential relationship between serum urate levels and PD, a meta-analysis was conducted in this present study by combining all available data together. 2 Materials and methods 2.1 Search strategies A computerized search of Pubmed, Web of Science, and the Cochrane Library up to Dec 2015 was conducted using the following search strategy: ªParkinson's diseaseº, (ªbloodº, ªplasmaº or ªserumº), and (ªuric acidº or ªurateº). The search was restricted to English language. The reference lists of relevant studies were also searched for possible studies meeting criteria. If there was an initial disagreement on studies to be included, discussion among researchers established universal agreement. A flowchart of information pertaining to identification, screening, eligibility, and final studies included was constructed according to ªPreferred Reporting Items for Systematic Reviews and Meta-analysesº (PRISMA) guidelines [ 25 ]. 2 / 13 2.2 Inclusion (...truncated)


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Min Wen, Bo Zhou, Yun-Hua Chen, Zhao-Lei Ma, Yun Gou, Chun-Lin Zhang, Wen-Feng Yu, Ling Jiao. Serum uric acid levels in patients with Parkinson’s disease: A meta-analysis, PLOS ONE, 2017, Volume 12, Issue 3, DOI: 10.1371/journal.pone.0173731