Influence of serum uric acid levels on prognosis and survival in amyotrophic lateral sclerosis: a meta-analysis.

Uric acid (UA) is considered to be one of the most important antioxidants in the blood. While high UA levels are found in many disease states, low UA levels are reported in many neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis (ALS). Various studies showed consistently that ALS patients have lower serum UA levels than healthy individuals, more prominently in cases with bulbar onset and longer disease duration. A systematic search of PubMed was conducted to retrieve published studies on UA levels in ALS patients. A meta-analysis was performed on published studies comparing UA levels between ALS patients and controls. This meta-analysis revealed highly statistically significant (p < 0.0001) lower UA levels and a very large size effect in 311 ALS patients compared to 515 controls as a group, as well as calculated for men and women separately. Many studies indicate that patients with neurodegenerative diseases, including ALS, have low UA levels. Our meta-analysis strengthens these findings in ALS patients, demonstrating highly statistically significant (p < 0.0001) lower UA levels in patients compared to controls, with very large total size effect, more prominent in men.