Low Plasma Total Iron-Binding Capacity and Bioimpedance Phase Angle Are Associated with Major Adverse Cardiovascular Events and Mortality in Maintenance Hemodialysis Patients: A Retrospective Cohort Study in Vietnam

Abstract

Background: Cardiovascular complications represent a major contributor to morbidity and mortality among patients with chronic kidney disease (CKD), especially those undergoing maintenance hemodialysis (MHD), because of complex metabolic, inflammatory, and nutritional disturbances. Objectives: We aimed to investigate the relationship between plasma total iron-binding capacity (TIBC) concentration and low phase angle (PhA) with major adverse cardiovascular events (MACEs) and mortality in patients undergoing MHD. Methods: A retrospective cohort study was conducted in 182 patients undergoing MHD, with a mean age of 50.21 ± 15.45 years; 51.6% were male, and 48.4% were female. Plasma TIBC levels were measured using an enzyme-linked immunosorbent assay (ELISA), and PhA was determined by automatic segmental bioimpedance analysis (BIA) at 50 kHz using an InBody S10 device. Major adverse cardiovascular events were diagnosed by a cardiologist, and all-cause mortality data were collected over a 3-year follow-up period from study baseline. Results: The prevalence of MACEs was 26.4%, and all-cause mortality was 12.6%. Higher plasma parathyroid hormone (PTH) and high-sensitivity C-reactive protein (hs-CRP) levels and lower plasma TIBC and PhA values were independently associated with both MACEs and mortality. TIBC and PhA were valuable predictors of MACEs, with areas under the curve (AUCs) of 0.796 and 0.895, respectively (P < 0.001), and all-cause mortality, with AUCs of 0.843 and 0.898, respectively (P < 0.001). Conclusions: Low plasma TIBC and low bioimpedance-derived PhA are associated with a higher risk of MACEs and all-cause mortality in patients undergoing MHD.