Elevated Interleukin-6 Is Associated with an Increased Risk of Long-Term Arteriovenous Fistula Failure for Dialysis

Background/Objectives: The autologous arteriovenous fistula (AVF) is the preferred choice for vascular access in patients with end-stage kidney disease (ESKD) undergoing maintenance hemodialysis. However, in the long term, the primary patency of AVF is suboptimal, with an AVF failure of approximately 30% in one year. The aim of this study is to examine how the pre-operative baseline levels of interleukin-6 (IL-6) affect long-term AVF failure. Methods: This retrospective, observational study involves ESKD patients admitted to the Vascular Surgery Clinic for AVF creation from January 2020 to December 2023. Ultimately, a total of 91 patients whose AVFs matured and began dialysis were enrolled. Prior to surgery, each patient underwent a thorough blood sample collection, with IL-6 levels assessed. The patients were categorized into two groups: those with functioning AVFs and those with dysfunctional AVFs. Their progress was monitored via a review of medical records, telephone interviews, or direct contact. Following the surgery, patients were observed for an average of 1.53 ± 0.94 years. Results: During the follow-up, patients who experienced AVF failure had a higher incidence of diabetes mellitus (p = 0.019) and active smoking (p = 0.012), as well as higher levels of IL-6 (p < 0.001). At ROC analysis, we found a strong association between IL-6 value and AVF failure (AUC: 0.814, p < 0.001), with an optimal cut-off value of 7.08 (76.5% Sensitivity and 79.7% Specificity). Furthermore, at the survival curve Kaplan-Meier analysis, we observed a higher occurrence of AVF failure in patients with baseline IL-6 values above the median (p = 0.004), in tertile 3 (p = 0.002), and above the optimal cut-off value (p < 0.001). At cox-regression analysis, elevated baseline IL-6 levels are associated with AVF Failure (HR: 2.23, p < 0.001). Conclusions: In the current study, we demonstrated that elevated IL-6 levels at baseline are associated with long-term AVF failure, independent of age, sex, and cardiovascular risk factors.