[Relationship between bioelectrical impedance analysis-derived fluid status and nutritional indicators and the...

Objective: To explore the relationship between bioelectrical impedance analysis (BIA)-derived fluid status and nutritional indicators and the prognosis in patients undergoing maintenance hemodialysis (MHD). Methods: A retrospective cohort study was conducted. The clinical data of MHD patients in Jiangsu Province Hospital between January 2014 and December 2016 were analyzed. BIA data of healthy volunteers in Gulou District, Nanjing City, collected between April and October 2022, were used to determine the cut-off value of body cell mass index (BCMI). Referring to previous research, using 0.15 as the cut-off value for the ratio of overhydration and extracellular water (OH/ECW). The data were transformed into binary variables based on these cut-off values to categorize patients into different groups. Kaplan-Meier analysis was used to plot survival curves, and the Cox proportional hazards model was performed to analyze risk factors for all-cause mortality. Results: A total of 706 MHD patients (407 males and 299 females) were included, aged (54±15) years. MHD patients were classified into four groups based on whether BCMI was<5.4 kg/m² and OH/ECW was≥0.15, which included non-overhydration and non-malnutrition group, overhydration group, malnutrition group, and overhydration and malnutrition group, with 269, 186, 151, and 100 patients, respectively. During a median follow-up of [M(Q₁, Q₃)] 33 (26, 37) months, 162 patients died. Kaplan-Meier analysis showed that the median survival periods of the four groups were 52 months (95%CI: 41-54 months), 46 months (95%CI: 44-49 months), 37 months (95%CI: 34-40 months), and 34 months (95%CI: 30-38 months), respectively, with a statistically significant difference (P<0.001). The 1-year survival rates were 95.5%, 93.5%, 92.1%, and 88.0% (P<0.001), respectively, and the 2-year mortality rates were 92.6%, 87.1%, 83.4%, and 77.0% (P<0.001), respectively. Multivariate Cox regression analysis showed that compared with non-overhydration and non-malnutrition group, the risk of all-cause mortality increased by 1.18 times in the malnutrition group (HR=2.18, 95%CI: 1.29-3.71, P=0.004), and by 1.59 times in the overhydration and malnutrition group (HR=2.59, 95%CI: 1.48-4.54, P=0.001). Conclusions: BIA-derived fluid status and nutritional indicators are associated with the prognosis of MHD patients. Compared with patients without fluid overload and malnutrition, patients with malnutrition and fluid overload have an increased risk of all-cause mortality.