Estimation of Body Composition in Dialysis Patients using Segmental Bioimpedance

Accurate estimation of body muscle, fat and fluid volumes in dialysis patients is an important factor to predict outcomes of the disease. Bioimpedance spectroscopy (BIS) has been used to measure extracellular (Re) and intracellular resistance (Ri) with whole body (wBIS) and segmental (sBIS) measurement. 40 stable HD patients (22m/18f, age 54.7 +/- 11 yrs, height (H) 1.67 +/- 0.94 m, weight (Wt) 77.7 +/- 17 kg) were studied with wB1S and sBIS compared to the gold standard measurements by MRI and tracer dilution assays (D(2)O and NaBr) pre dialysis. Multiple linear regression models were constructed with body compartment estimates from the gold standard methods as the dependent variables and bioimpedance-derived resistances, Wt, H, and age as independent variables. The results of estimation for fat (r(2)=0.96 and r(2)=0.91), for muscle (r(2)=0.9 and r(2)=0.88) and for ECV (r(2)=0.73 and r(2)=0.59) were from sBIS and wBIS model respectively. In conclusion, the sBIS model is useful to assess body composition in dialysis patients.