Using Bioimpedance Spectroscopy for Diagnosis of Malnutrition in Chronic Kidney Disease Stage 5—Is It Useful?

Malnutrition is common in chronic kidney disease stage 5 (CKD5) and has negative clinical impacts. The aim of the present study is to evaluate bioimpedance spectroscopy (BIS) in diagnosing malnutrition in CKD5 including hemodialysis and peritoneal dialysis patients (CKD5D) using cutoff values for fat-free mass index (FFMI) according to the Global Leadership Initiative on Malnutrition criteria. Dual-energy X-ray absorptiometry (DXA) was used as a reference method. We performed a single-center cross-sectional diagnostic study of 90 patients with CKD5 or CKD5D. BIS-derived FFMI estimates were significantly higher compared with those obtained by DXA (18.5 ± 2.6 vs.17.8 ± 2.0, P < .05). The mean difference in FFMI estimates between the methods (DXA–BIS) and Bland-Altman 95% limits of agreements is –0.38 (2.76, –3.52) kg/m2. Overhydration (B = 0.67, P < .001), age (B = 0.02, P = .037), and interactions between overhydration and CKD5 subgroups (P = .034) independently predicted bias in BIS-derived FFMI. BIS-derived FFMI showed poor sensitivity (64%) and positive predictive value (48%) in diagnosing malnutrition in the present study population. The present study showed a limited agreement between estimates of FFMI derived by BIS and DXA due to a large interindividual variation. Using BIS as a clinical tool for assessing FFMI has limited accuracy and poor sensitivity in diagnosing malnutrition in patients with CKD5 and CKD5D.