Comparison of three methods for the determination of body fat in patients on long-term hemodialysis therapy

Objective: To compare three simple methods of body composition analysis for the assessment of body fat in patients on long-term hemodialysis therapy. Design: Cross-sectional study using the skinfold thickness, bioelectrical impedance analysis, and near-infrared interactance techniques after a hemodialysis session. Subjects/setting: Ninety clinically stable patients (57 male/33 female) undergoing hemodialysis at the Dialysis Unit of the Federal University of São Paulo. Statistical analysis Analysis of variance, intraclass correlation coefficient, and Bland-Altman plot analysis were used for the comparative analysis between the methods. Results: Body fat measurements obtained by skinfold thickness (13.5+/-6.2 kg) and bioelectrical impedance analysis (13.7+/-6.7 kg) were similar, whereas those measured by near-infrared interactance (11.3+/-5.1 kg) were significantly lower in comparison with skinfold thickness and bioelectrical impedance analysis (P<.001). The strongest intraclass correlation coefficient was found between bioelectrical impedance analysis and skinfold thickness (r=0.87), and near-infrared interactance vs skinfold thickness and bioelectrical impedance analysis methods yielded r=0.78 and r=0.76, respectively. Near-infrared interactance showed a progressive underestimation of body fat values in comparison with the bioelectrical impedance analysis technique in patients with higher amount of adiposity. Conclusion: In our study, we cannot consider that one method of body composition analysis is more accurate than the other because we did not apply a gold standard method. However, the most simple, long-established, and inexpensive method of skinfold thickness seems to be still very useful to the dietitians' routine for assessing body fat in patients on long-term hemodialysis therapy.