Serum uric acid levels in multiple sclerosis patients inversely correlate with disability

Uric acid (UA) is an endogenous antioxidant. Some studies have described that multiple sclerosis (MS) patients have lower serum UA levels than controls, although it has not been established whether UA is primarily deficient, or secondarily reduced due to its scavenging activity. UA has also been proposed as an indicator of disease activity. We, retrospectively, reviewed 478 serum UA levels obtained in 94 MS patients. Ninety samples were collected during a relapse. Correlation between UA levels obtained during a relapse or in a relapse-free period, and comparison between UA and expanded disability status scale (EDSS) score was tested using a two-tailed Student's t test and Spearman correlation coefficients test. UA levels were significantly lower when measured during a relapse (n 90) than in a remission period (n 368) (r -0.16, p 0.003) UA levels measured outside a relapse inversely correlated with EDSS score (r -0.15, p 0.001). Lower uric acid levels in MS patients are associated with clinical relapse. This is the first description of an inverse correlation of serum UA levels with disability as assessed by EDSS score.