RESUMO
OBJECTIVES: To evaluate the relationship between the expression level and biologic role of YKL-40 in bipolar disorder (BD). METHODS: This case-control study was conducted in the Faculty of Medicine, Canakkale Onsekiz Mart University, Canakkale, Turkey in 2015. One hundred and four patients diagnosed as having bipolar disorder (DSM5 criteria), and 96 participants were included as healthy controls in this study. A human YKL-40 enzyme-linked immunosorbent assay (ELISA) kit was used to measure the serum YKL-40 levels. As independent variables, we collected data on C-reactive protein (CRP), demographic variables, and medications. Results: The mean YLK-40 levels for the BD was 2723.5±543.8 pg/ml and control groups was 2132.5±576.3 pg/ml (t=7.42, p less than 0.001). The mean CRP levels for the BD was 0.4±0.6 mg/dl and control groups was 0.4±0.7 mg/dl (t=0.02, p=0.985). The receiver operating characteristics (ROC) analysis revealed an area under the curve (AUC) of YKL-40 in the diagnosis of BD as 0.79 (95% confidence interval [CI]: 0.72-0.85) with a sensitivity of 82.7% and specificity of 68.1% at a cutoff level of 2307.1 pg/ml. The use of antidepressants, antipsychotics, mood modifiers, and the presence of any comorbidity was not related to the YKL-40 levels (p greater than 0.05). Conclusion: With acceptable sensitivity and specificity levels, the YKL-40 can be utilized as a marker in the diagnosis and follow-up of BD.