Association of brain-derived neurotrophic factor and interleukin-6 serum levels with depressive and anxiety symptoms in hemodialysis patients.

Objective: This study assessed the possible association of serum brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) with depressive and anxiety symptoms in hemodialysis (HD) patients.

Method: An analytical cross-sectional study was conducted over 274 HD patients from March to October 2017. The Hospital Anxiety and Depression Scale (HADS) was utilized to evaluate depressive (HADS-D) and anxiety (HADS-A) symptoms. The HADS-D/A is a self-report instrument that has a maximum score of 21. Serum BDNF and IL-6 were measured using enzyme-linked immunosorbant assay (ELISA).

Results: Serum IL-6 was significantly higher in patients with depressive symptoms compared to normal (20.47 ± 4.27 pg/mL for HADS-D ≥11 versus 9.26 ± 1.59 pg/mL for HADS-D <7, p = 0.014). Multivariable regression analysis revealed that IL-6, education level, hypertension, and dialysis duration were significant predictors of HADS-D. Also, gender, education level, hypertension, and the number of dialysis sessions/week were significant predictors of HADS-A. Significant positive correlation was shown between HADS-D and IL-6 (r = 0.1729, p = 0.004).

Conclusion: Collectively, HD patients with depressive symptoms showed higher levels of IL-6, supporting previous findings that the circulating inflammatory mediator IL-6 can be used as a biomarker for prediction of depressive symptoms in HD patients. Further longitudinal or interventional studies are needed to further validate this association.