Abstract: SA-PO180

The Use of Phase Angle to Evaluate Fluid Status in Dialysis Patients

Session Information

Category: Nutrition, Inflammation, and Metabolism

  • 1401 Nutrition, Inflammation, Metabolism

Authors

  • Rosales, Laura, Renal Research Institute, New York, New York, United States
  • Zhu, Fansan, Renal Research Institute, New York, New York, United States
  • Preciado, Priscila, Renal Research Institute, New York, New York, United States
  • Thwin, Ohnmar, Renal Research Institute, New York, New York, United States
  • Tao, Xia, Renal Research Institute, New York, New York, United States
  • Thijssen, Stephan, Renal Research Institute, New York, New York, United States
  • Kotanko, Peter, Renal Research Institute, New York, New York, United States
Background

Phase angle (PA) has been suggested as an indicator for assessing body composition and fluid status in hemodialysis (HD) patients. PA is calculated by the ratio of reactance and resistance. Resistance represents body water content and reactance relates to body cell mass. The primary aim of this study was to evaluate the relationship between peridialytic fluid and phase angle changes in different fluid status in HD patients and healthy subjects (HS).

Methods

Ten HD patients (8 males, age 58.1±12 years, height 167±11 cm) and 12 healthy subjects (HS; 7 females, age 33±6 years, height 169±10 cm) were studied with the Seca mBCA 514 bioimpedance device (Seca North America, Chino, CA USA). Resistance (R, Ohm), reactance (Xc, Ohm), impedance (Imp, Ohm), and phase angle (PA, degrees) were measured pre- and post-HD treatment. HS were measured once. R, Xc, Imp and PA were compared between pre- and post-HD. In addition, we compared the post-HD levels with HS using 1-way ANOVA. Pre- and post-HD weights and body mass index (BMI) were recorded.

Results

Peridialytic body weight reduction was 2.63±0.54 kg. This weight change was accompanied by increased in PA and decreased in Xc. Average PA and Xc differed significantly from various hydration groups (pre-, post-HD and HS) by a nonparametric test (Fig. 1 A and C). Of note, pre- and post-HD R and Imp did not differ significantly in HD patients (Fig. 1 B and D). BMI and PA were not correlated. Coefficient of variation of PA is 12.7% in HS group.

Conclusion

PA reflects peridialytic fluid status changes and thus is useful for evaluating relative changes in a given patient. However, PA may not be used to identify normal fluid status due to its large variability in HS (Fig 1 A). This variability is possibly due to the fact that PA is computed as the ratio of two variables, resistance and reactance, which represent different body components.

Fig. 1