2023 Volume 56 Issue 11 Pages 421-428
To elucidate the effects of ultrafiltration of water in hemodialysis (HD) on total body water (TBW) and body fat mass (FM), both of which were measured by segmental multi-frequency bioelectrical impedance analysis (sMF-BIA), we evaluated the relationship between the ultrafiltered water volume and TBW as well as FM before (pre-) and after (post-) HD in 67 HD patients. The mean ultrafiltration volume and change in TBW at pre- and post-HD were in good agreement for both male and female HD patients；however, the difference between the two tended to become greater with an increasing ultrafiltration volume. When the standard physiological hydration ratio of the fat-free mass (TBW/FFM), i.e., 0.73, was applied to that at post-HD, FM at pre-HD was theoretically estimated to be lower than that at post-HD, by about 37％ of the ultrafiltration volume. Both the estimated and measured values of FM at pre-HD were in good agreement for both males and females. In conclusion, a large ultrafiltration volume might affect TBW measured by sMF-BIA, suggesting that the measured FM may be affected by an increased TBW/FFM due to pre-HD overhydration.