Peripheral Uric Acid as a Biomarker in Individuals With Bipolar Disorder: A Case Control Study

Abstract Background: At present, no well-established biomarkers were ever found to distinguish unipolar disorder (UD) and bipolar disorder (BD). This study aimed to explore whether uric acid (UA) could be a biomarker to distinguish UD and BD. Methods: Peripheral UA of 119 patients with BD in acute stage (AS) and 77 in remission stage (RS), and 95 patients with UD in AS and 61 in RS were measured, so were 180 healthy controls. Differences in continuous variables among groups were assessed by the independent samples t-test and one-way analysis of variance. The chi-square test was applied to categorical data such as gender. Results: UA levels in BD group were higher than UD and HC groups regardless of the AS or RS, while differences in UA levels between UD group and HC group were not significant. Differences of UA levels between BD-M (bipolar mania/hypomania) and BD-D (bipolar depression) subgroups were not significant, and UA levels of BD-M and BD-D subgroups were higher than UD and HC groups. Only in UD group, UA levels of drug-use subgroup were higher than drug-naïve/free subgroup, but differences disappeared when analyzed stratified by sex; whether in drug-use or drug-naïve/free subgroup, differences of UA levels between BD-M and BD-D groups were not significant.Conclusion: The study suggests UA levels may be a biomarker of BD to distinguish from UD.