Application of bioelectrical impedance vector analysis to evaluate volume status of hemodialysis patients with hypertension / 中华肾脏病杂志

ABSTRACT

Objective:To evaluate the volume status of hemodialysis patients with hypertension by bioelectrical impedance vector analysis, and investigate the effect of high volume status on the prognosis of patients with hypertension.Methods:The study subjects came from the patients with pre-dialysis systolic blood pressure>160 mmHg (mean systolic blood pressure of 6 times of treatment) in the Affiliated BenQ Hospital of Nanjing Medical University. According to the volume status assessed by bioelectrical impedance vector analysis, patients were divided into two groups: fluid overload group and non-overload group (including normal fluid status and fluid decline). The clinical data, laboratory test results, ratio of intracellular and extracellular water (ICW and ECW), body cell mass, lean body mass and the percentage of total body weight, fat percentage of body weight, resistance/height, reactance/height, phase angle and illmarker were compared between two groups. Kaplan-Meier survival curve was used to compare the difference of survival rate between the two groups.Results:A total of 51 hemodialysis patients with hypertension were enrolled in this study, including 19 patients in fluid overload group and 32 patients in non-overload group (27 patients with normal volume status and 5 patients with decreased volume). The levels of albumin, prealbumin, hemoglobin, hematocrit and serum phosphorus in patients with fluid overload decreased significantly compared with non-overload patients (all P<0.05), and the proportion of lymphocytes increased in fluid-overload patients ( P<0.05). The ratio of extracellular water and illmarker index in fluid overload group were significantly higher than those in the other group (both P<0.01). However, phase angle, resistance/height, reactance/height were lower than those in patients with non-overload (all P<0.01). After 20 months of clinical observation, the control rate of blood pressure (pre-dialysis systolic blood pressure<160 mmHg) in fluid overload group was lower than that in the non-overload group (26.3% vs 43.8%), but not statistically significant ( P=0.218). The all-cause mortality rate of patients in the fluid overload group was higher than non-overload group (26.3% vs 15.6%). Kaplan-Meier survival curve analysis suggested that the difference in survival rate between the two groups was not statistically significant. Conclusions:The extracellular fluid of hemodialysis patients with hypertension and fluid overload increases significantly, and the nutritional status evaluation index decreases compared with that of patients without increased volume. Increased proportion of lymphocytes may be related to the micro-inflammatory status. Blood pressure is more difficult to control in hypertensive patients with fluid overload and the clinical prognosis can be worse in patients without increased volume.