Comparison of Clinical Features, Serum Lipid, and Uric Acid Levels in Patients with Unipolar Depression and Bipolar Depression

Background: The level of uric acid and serum lipids has been suggested as a possible biomarker of bipolar disorder. We aimed to investigate the differences in clinical features and serum levels of lipids and uric acid in patients with bipolar depression or unipolar depression in order to distinguish them. Methods: The clinical data of 53 patients with unipolar depression (unipolar group) and 61 patients with bipolar depression (bipolar group), who all met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders-IV of the American Psychiatric Association, were compared with each other retrospectively. The serum levels of uric acid and lipids (including total cholesterol, lowdensity lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides) were measured after hospital admission. The Statistical Package for the Social Science version 22.0 software was used for statistical analysis, and logistic regression was employed to identify the susceptible factors of bipolar depression. Results: Taking into account confounding factors, logistic regression analysis revealed that the high levels of uric acid (odds ratio = 1.016, P =.001) and low levels of triglycerides (odds ratio = 0.457, P =.025) were significantly correlated with bipolar depression. Conclusion: It has been demonstrated from this study that individuals with bipolar depression have higher serum uric acid levels and lower triglyceride levels than unipolar depression ones. Therefore, serum levels of uric acid and triglycerides might have the potential to be the biomarkers for differential diagnosis between bipolar and unipolar depression.