Is 3-Compartment Bioimpedance Spectroscopy Useful to Assess Body Composition in Renal Transplant Patients?

Background Metabolic disorders, in particular weight gain, increase cardiovascular mortality risk and can cause serious problems after renal transplantation. Weight and body mass index are imprecise indicators of nutritional status. Accurate determination of the body compositionof renal transplant patients is essential; therefore, a simple tool that allows appropriate patient monitoring is crucial. Design A new device, the Body CompositionMonitor (BCM, Fresenius Medical Care, Bad Homburg, Germany), expresses body weight in terms of adipose tissue, lean tissue mass, and excess fluid. We compared the performance of this 3-compartment model with dual-energy X-ray absorptiometry (DEXA) as a reference method in determining body compositionin a renal transplant population. Subjects Thirty-three clinically stable renal transplant patients were studied. Bland-Altman plotsand Passing-Bablok regression were used to compare methods. Results Mean lean mass was 51.8 ± 12.3 kg with DEXA and 39.0 ± 9.9 kg with BCM. Despite the Passing-Bablok regression failing to find significant differences, the predictive value of BCM for DEXA was poor. Mean fat mass was 19.4 ± 9.7 kg with DEXA and 30.0 ± 16.0 kg with BCM. The slope of the regression line of BCM over DEXA significantly differed from 1. Conclusion We conclude that, in this population, these methods cannot be substituted for one another.