2026 Volume 59 Issue 8 Pages 460-469
The edema index (ECW/TBW), which is the ratio of extracellular water (ECW) to total body water (TBW) measured by bioelectrical impedance analysis (BIA), has been reported as one indicator for determining dry weight (DW) in dialysis therapy. Standard ECW/TBW values range from 0.360 to 0.400, and those exceeding 0.400 are considered high. However, ECW/TBW is influenced not only by fluid volume but also factors such as age, nutritional status, and skeletal muscle mass index. Referring to reports by Ueno, Seino, and Sasaki using InBody, we considered sex, age, muscle mass, presence of diabetes mellitus (DM), and hypoalbuminemia (Alb) as factors affecting ECW/TBW. We calculated a standard ECW/TBW for each patient and used this value in the InBody calculation formula to estimate ideal DW and evaluate its utility. The calculated ideal DW showed a strong correlation with clinical DW (r＝0.997, p ＜0.001). While ECW/TBW showed a weak correlation with the difference between post‒dialysis body weight and clinical DW (Δclinical DW) (r＝－0.167, p ＝0.001), there was a good positive correlation with the difference between post‒dialysis body weight and ideal DW (Δideal DW) (r＝0.892, p ＜0.001). Therefore, ideal DW calculated using a patient‒specific standard ECW/TBW may better reflect the degree of fluid overload, and so is considered a useful indicator for DW determination.
