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.