A cross-sectional study on the association of serum uric acid levels with depressive and anxiety symptoms in people with epilepsy

BACKGROUND: High serum uric acid (SUA) levels may provide protection against depression and anxiety through its defensive role in oxidative damage. The aim of this study was to test the hypothesis of the independent associations of lower SUA levels with depressive and anxiety symptoms among patients with epilepsy (PWE). METHODS: A cross-sectional study was performed among 320 PWE aged ≥18 years old in Northeast China. The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E; Chinese version) and the Generalized Anxiety Disorder-7 scale (GAD-7; Chinese version) were used as screening tools for depressive and anxiety symptoms for PWE. Serum uric acid levels were measured. The associations of SUA levels with depressive and anxiety symptoms were assessed by using binary logistic regression models, with adjustment for the related risk factors (P< 0.05). RESULTS: Lower SUA tertiles were significantly associated with higher C-NDDI-E and GAD-7 scores compared with the higher two tertiles (p=0.001, and p= 0.002). Patients with depressive symptoms exhibited significantly lower SUA levels compared to those without depressive symptoms (p< 0.001). SUA levels of patients with anxiety symptoms were significantly lower than those of patients without anxiety symptoms (p< 0.001). The first and second SUA tertiles were associated with depressive symptoms, with the third tertile group as the reference group, after adjusting for confounders (first tertile: OR = 4.694, 95% CI = 1.643~ 13.413, P = 0.004; second tertile: OR = 3.440, 95% CI = 1.278~9.256, P = 0.014). However, The first and second SUA tertiles were not associated with the risk of anxiety symptoms compared with the third tertile in the adjusted logistic regression model (First tertile: OR = 1.556, 95% CI = 0.699~3.464, P = 0.279; second tertile: OR = 1.265, 95% CI = 0.607~2.635, P = 0.530). CONCLUSION: We found that lower SUA levels were independently associated with depressive symptoms but not with anxiety symptoms among PWE. Further well-designed prospective cohort studies are required to determine the causality of the associations and to further clarify the mechanisms of SUA in depressive symptoms.