Abstract: 【Abstract】Objective To explore the role of post-dialytic overhydration (OH) determined by bioelectrical impedance technique in the prediction of all- cause death in maintenance hemodialysis (MHD) patients. Methods A total of 117 MHD patients without edema from Peking University People's Hospital were recruited for the observation. Their total body water (TBW), extracellular water (ECW), intracellular water (ICW), fat mass and muscle mass after dialysis were measured by bioelectrical impedance analyzer. The ECW/TBW ratio higher than that of normal upper limit after hemodialysis was defined as post-dialytic OH. Blood pressure, laboratory tests and echocardiography were recorded. The primary endpoint was all-cause death in the follow-up period of 4 years. Multivariate COX regression analysis was conducted to explore the predictive effect of post-dialytic OH on all-cause death in MHD patients using all-cause death as the dependent variable, post-dialytic OH as the independent variable, and statistically significant variables in univariate analysis and clinically significant variables in previous studies as the correction variables. Results ①A total of 117 patients (73 males and 44 females, average age 58±15 years old) on MHD for 67 (39, 120) months were included in this study. They were followed up for 4 years, and 21 cases died (17.9%) and 96 cases survived in the
follow-up period. ②Multivariate COX regression analysis showed that post-dialytic OH was an independent risk factor for all-cause death (HR=17.459, 95% CI 2.801～108.832, P=0.002) in MHD patients after adjusting for a variety of factors. Conclusions Post-dialytic ECW/TBW ratio was a sensitive biomarker of volume status in MHD patients without evident edema. Post-dialytic OH was an independent risk factors for all-cause death in MHD patients. Therefore, volume management should be carefully conducted in MHD patients.

Key words: Hemodialysis, Ratio of extracellular water to total body water, Overhydration, Death, Visceral fat