Gout Does Not Decrease the
Risk of Parkinson’s Disease: A Systematic Review and Meta-analysis

Background/Purpose: Uric 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, EMBASE and the Cochrane database from
inception to April 2015 using the terms for gout combined with the terms for
Parkinson’s disease.  A manual search of references of selected articles
was also performed.  The inclusion criteria were as follows: (1) cohort or
case-control study evaluating the risk of PD among patients with gout (2) odds
ratio (OR), relative risk (RR) or hazard ratio (HR) or standardized incidence
ratio (SIR) with 95% confidence interval (CI) were provided (3) subjects
without gout and subjects without PD were used as control group in cohort and
case-control study, respectively.  Study eligibility was
independently determined by the two investigators.

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 random-effect model,
generic inverse variance method of DerSimonian and Laird. Statistical
heterogeneity was assessed using the Cochran’s Q test and I²
statistics. 

Results: Out of 351 potentially relevant articles,
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 of this
meta-analysis was high with an I² of 87% (Figure 1). The results
were not significantly different between males and females (RR 0.85; 95% CI,
0.68 to 1.06 and RR 0.95; 95% CI, 0.76 to 1.19, respectively).

Conclusion: This study did not support the inverse
relationship between gout and risk of PD