Association between serum uric acid level and multiple system atrophy: A meta-analysis

•Our aim is to evaluate the relationship between serum UA level and MSA.•Lower serum level of UA is associated with an increased risk of MSA.•The correlation above is significant in males but not in females. Lower serum uric acid (UA) levels are considered to be related to the risk to develop many neurodegenerative disorders. However, the association between serum UA level and multiple system atrophy (MSA) remains controversial. The aim of this meta-analysis was to evaluate the relationship between serum UA level and MSA. PubMed, Web of Science, Embase, Cochrane Library and China National Knowledge Infrastructure (CNKI) were searched for eligible studies. Standardized mean difference (SMD) and 95% confidence intervals (95% CI) were calculated in a fixed-effects model or a random-effects model when appropriate. Subgroup analyses were carried out based on gender. A total of 6 eligible studies involving 547 MSA patients and 637 healthy individuals were identified. Meta-analysis results revealed that individuals with MSA had lower sera levels of UA as compared with healthy controls (pooled SMD is −0.51, 95%CI: −0.88 to −0.14; p = 0.006). The subgroup analysis to detect sex differences showed that the pooled SMD was −0.61 (95% CI: −0.82 to −0.40; p