Impact of Transferrin Saturation on All-Cause Mortality in Patients on Maintenance Hemodialysis

Background: Transferrin saturation (TSAT) is an index that represents the iron-binding capacity of transferrin, which is the main transport protein for iron, and is widely used to evaluate iron status. Objective: To evaluate the prognostic importance of TSAT in Japanese patients on maintenance hemodialysis (MHD). Methods: A total of 398 patients on MHD were recruited and divided into 3 groups on the basis of their baseline TSAT levels (<20, 20-40, and >40%). Results: There was no difference in the proportion of patients on erythropoiesis-stimulating agents or iron supplements between the 3 groups. During a mean follow-up period of 52.2 +/- 1 6.3 months, 130 patients died of cardiovascular causes (n = 63, 15.8%) or infection (n = 47, 11.8%). Compared with the reference group (TSAT 20-40%), patients with a TSAT <20% had a significantly higher all-cause mortality rate (6.44 vs. 9.55 events per 100 patient-years, p = 0.0452). Kaplan-Meier analysis showed that all-cause mortality rate was significantly higher in patients with TSAT <20% than in the other 2 groups (p = 0.0353). Conclusions: Low TSAT was a significant independent risk factor for all-cause mortality in a cohort of Japanese patients on MHD. The findings of this study suggest that the adverse clinical outcomes in patients with low TSAT can be partly attributed to infection-related iron deficiency.