Gout is not associated with a lower risk of Parkinson's disease: A systematic review and meta-analysis

Background: Uratic acid is a potent anti-oxidant and hyperuricemia is well-linked to a lower risk of Parkinson's disease (PD), one of the most common neurodegenerative disorders. However, data on gout, the major complication of hyperuricemia, remain unclear. Methods: Two investigators independently searched published studies indexed in MEDLINE, and EMBASE from inception to April 2015 using the terms for gout combined with the terms for PD. The inclusion criteria were as follows: (1) cohort or case-control study evaluating the risk of PD among patients with gout (2) odds ratio, relative risk, hazard ratio or standardized incidence ratio were provided (3) subjects without gout and subjects with PD were used as controls in cohort and case-control study, respectively. RevMan 5.3 software was used to perform the statistical analysis. Point estimates and standard errors were extracted from individual studies and were combined by generic inverse variance method of DerSimonian and Laird. Statistical heterogeneity was assessed using the Cochran's Q test and I-2 statistics. Results: Three case-control studies and two cohort studies were identified and included in the data analysis. The pooled risk ratio of PD in patients with gout was 0.93 (95% CI, 0.79 to 1.09). The statistical heterogeneity was high with an 12 of 87%. The results were not significantly different between males and females (RR 0.89; 95% CI, 0.57 to 139 and RR 0.95; 95% CI, 0.76 to 1.19, respectively). Conclusion: This study did not provide support for an inverse relationship between gout and risk of PD. (C) 2015 Elsevier Ltd. All rights reserved.