Bioimpedance analysis highlights changes in body composition at the early stages of impairment of kidney transplant function

Objective: Kidney transplantation restores renal filtration, although it does not achieve the function of 2 native kidneys, and with time it may involute back to chronic renal failure. We hypothesized that bioelectrical impedance analysis (BIA) might highlight differences for body compartments among kidney transplants (Tx) with different filtration rates. Methods: Thirty transplantation patients (19 male, 11 female) were studied at 62.4+/-26.6 months postsurgery and were divided into 3 groups: good creatinine clearance (crCl, mL/min/1.73 m(2); >65.0), borderline (35.0<crCl<60.0), and bad (crCl <35.0). BIA was assessed 3 times in 1 year. Total body water, extracellular water (ECW), intracellular water (ICW), Na:K exchangeable ratio (Nae:Ke), and phase angle were studied. Healthy (n=11) and hemodialysis (n=11) groups were studied as well. Results: BIA showed no differences between healthy controls and good Tx, whereas both borderline and bad Tx presented a significantly higher ECW and lower ICW than either good Tx or normal controls. Only good crCl was different from predialysis. Conclusions: A good graft kidney manages to restore and maintain normal body composition, whereas with mild renal dysfunction a change in body compartments was observed, moving toward the body water composition of chronic renal failure patients. (C) 2004 by the National Kidney Foundation, Inc.