Association of systemic immune-inflammation index with protein-energy wasting and prognosis in patients on maintenance hemodialysis

Abstract

Objective: To explore the association of systemic immune-inflammation index (SII) with protein-energy wasting (PEW) and prognosis in maintenance hemodialysis (MHD) patients. Methods: A multicenter cohort study was conducted in 11 hemodialysis centers of Guizhou province from July to September 2019. The patients were divided into the PEW group and non-PEW group. After 12 months of follow-up, death was the endpoint event. Multivariate logistic regression analysis was used to assess the independent risk factors of PEW in MHD patients. The receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of SII for PEW, and the optimal cut-off value of SII was calculated. The Kaplan-Meier method was used to draw the survival curve, and log-rank test was employed to compare the difference of survival rate between the two groups. Results: A total of 859 patients were included [540 males and 319 females, aged (54±15) years], and there were 220 cases (25.6%) and 639 cases (74.4%) in PEW and non-PEW groups, respectively. SII was higher in the PEW group than that of the non-PEW group [600 (440, 915) vs 475 (353, 633), P<0.01]. Multivariate logistic regression analysis showed that SII was an independent predictor for PEW (OR=1.001, 95%CI: 1.000-1.002, P=0.02). ROC curve analysis showed that the area under the curve for SII to predict PEW in MHD patients was 0.725 (95%CI: 0.683-0.766), with the sensitivity and specificity of 69% and 70%, respectively. All patients were followed up for 12 months, and 45 died (with a mortality rate of 5.24%). Patients were divided into SII>520 group and SII≤520 group according to the optimal cut-off value, and subsequent Kaplan-Meier survival analysis showed that the 1-year cumulative survival rate of the SII>520 group (92.3%) was lower than that of SII≤520 group (97.1%) (χ2log-rank=9.707, P=0.002). Further subgroup analysis revealed that, in PEW patients with MHD, the 1-year cumulative survival rate of the SII>520 group (88.5%) was also lower than that of SII≤520 group (92.3%) (χ2log-rank=7.226, P=0.007). Conclusion: SII is an independent risk factor for PEW in MHD patients, and the higher the SII level, the lower the long-term survival rate and the prognosis.