Clinical significance of serum interleukin-6 levels in patients with chronic kidney disease

Introduction and aim. Elevated levels of interleukin-6 (IL-6) in serum and kidney tissues are associated with the development and progression of chronic kidney disease (CKD). Although the role of pro-inflammatory cytokines, such as IL-6, in the development of cardiovascular complications is well studied, the relationship between serum IL-6 levels and CKD markers remains unclear. This study investigated the clinical significance of serum IL-6 levels in patients with CKD. Material and methods. Participants were divided into two groups based on estimated glomerular filtration rate (eGFR): group 1 (n=86) with eGFR >60 mL/min and group 2 (n=74) with eGFR <60 mL/min. The CKD Epidemiology Collaboration equation was used to calculate eGFR from serum creatinine and cystatin C levels to assess CKD severity. Results. Systolic blood pressure was higher in Group 2 than in Group 1 (138±22 mmHg vs. 129±19 mmHg; p<0.05). Serum IL-6 levels were also higher in group 2 (3.095 [interquartile range: 1.528–6.547] pg/mL) than in group 1 (1.711 [interquartile range: 0.920– 3.342] pg/mL; p <0.05). Serum IL-6 levels were strongly correlated with eGFR in multivariable-adjusted linear regression analysis. Conclusion. IL-6 levels increased in patients with CKD with an eGFR <60 mL/min, and this increase was associated with eGFR and diastolic blood pressure.