#3437 THE ASSOCIATION OF INTERLEUKIN-6 TO ALBUMIN RATIO WITH MORTALITY IN PATIENTS WITH KIDNEY FAILURE

Abstract

Abstract Background and Aims Systemic inflammation - characterized by high interleukin-6 (IL-6) and low albumin circulating concentrations - associates with worse outcomes in patients with kidney failure (KF). We examined the value of IL-6 to albumin ratio (IAR) to stratify risk of death in KF patients. Method In 435 incident dialysis patients (median age 56 years, 61.8% male, 31% diabetes mellitus (DM), 38.4% cardiovascular (CV) disease (CVD)), plasma IL-6 and albumin were measured at baseline to calculate IAR. We performed receiver operating characteristic curve (ROC) to compare the discriminatory performance of albumin, IL-6 and IAR for predicting all-cause and CV mortality. We divided patients into IAR tertiles and analysed: 1) cumulative incidence of all-cause mortality and CV mortality censored for renal transplantation during follow up of up to 60 months; 2) the association of IAR and all-cause and CV mortality risk according to Fine-Gray analysis taking renal transplantation as competing risk; and 3) the restricted mean survival time (RMST) and differences of RMST (∆RMST) between IAR tertiles to describe quantitative differences of survival time. Results Among 435 patients, 146 patients (33.6%) died, and 175 (40.2%) patients underwent renal transplantation during median 24.9 months of follow-up; 83 (56.8%) of the 146 deaths were due to CVD. The area under the ROC curve (AUC) of IAR (0.696 for all-cause mortality; 0.657 for CV mortality) was higher than that of both albumin and IL-6. As shown in Fig. 1 A and B: 1) the cumulative incidence of all-cause and CV mortality of patients in middle and high IAR tertiles was significantly higher than in low IAR tertile; 2) higher IAR associated with higher risk of all-cause (sub-hazard ratio (sHR) 1.93, 95% confidence interval (CI) 1.22-3.06 for high IAR tertile) and CV mortality (sHR 1.99, 95% CI 1.03-3.87 for middle IAR tertile) risk after adjusting for age, sex, DM, CVD, and smoking; and 3) ∆RMST at 59 months showed shorter survival time in middle and high IAR tertiles compared with low IAR tertile for all-cause (∆RMST -6.21 months for middle vs low tertile; ∆RMST -11.4 months for high vs low tertile) and CV mortality (∆RMST -4.73 months for middle vs low tertile; ∆RMST -7.49 months for high vs low tertile). Conclusion Higher IAR was independently associated with significantly higher all-cause and CV mortality risk in KF patients. These results suggest that IAR may provide useful prognostic information in patients with KF.