Comparison of bioimpedance equations and dual-energy X-ray for assessment of fat free mass in a Chinese dialysis population

Figures & data

Table 1. Comparison of anthropometric, BIA characteristics and clinical data in dialysis patients and healthy adults.

Parameters	HD	PD	Healthy adults	p
	(n = 50)	(n = 52)	(n = 30)
Age (y)	45.80 ± 11.37	46.35 ± 11.10	44.13 ± 11.64	0.69
Male (n,%)	33 (66.0)	28 (53.8)	18 (60.0)	0.46
Female (n,%)	17 (34.0)	24 (46.2)	12 (40.0)
Height (cm)	166.37 ± 9.01	165.49 ± 8.43	167.73 ± 8.13	0.52
Weight (kg)	69.01 ± 14.21	66.11 ± 11.59	69.95 ± 12.14	0.34
BMI (kg/m^2)	24.81 ± 4.00	24.03 ± 3.07	24.88 ± 4.25	0.48
R50 (Ω)	484.25 ± 96.07	418.22 ± 85.75	533.61 ± 75.00	0.00
Xc50 (Ω)	47.16 ± 13.00	36.03 ± 12.26	56.69 ± 7.11	0.00
H²/R50	60.20 ± 16.10	68.92 ± 18.60	53.95 ± 9.55	0.00

H: height; BMI: body mass index; R₅₀: resistance at 50 kHz; Xc₅₀: reactance at 50 kHz.

Table 2. Evaluation of FFM estimated by BIA equations against DXA as reference method.

	Mean ± SD	p ^a	r ^b
HD (n = 50)
FFM-DXA	50.30 ± 10.69
BIA
FFM-Kyle	51.94 ± 11.60	0.46	0.98
FFM-Sun SS	55.29 ± 12.39	0.03	0.98
FFM-Segal	51.02 ± 10.39	0.73	0.97
FFM-TBW	50.72 ± 11.11	0.85	0.95
PD (n = 52)
FFM-DXA	50.39 ± 9.08
BIA
FFM-Kyle	53.83 ± 12.58	0.11	0.97
FFM-Sun SS	58.77 ± 13.59	0.00	0.96
FFM-Segal	51.58 ± 10.21	0.53	0.96
FFM-TBW	53.08 ± 11.30	0.18	0.95
Healthy volunteers(n = 30)
FFM-DXA	48.36 ± 8.79
BIA
FFM-Kyle	49.91 ± 8.53	1.00	0.96
FFM-Sun SS	52.11 ± 8.46	0.64	0.97
FFM-Segal	49.99 ± 8.23	1.00	0.97
FFM-TBW	48.37 ± 7.82	1.00	0.96

Estimates of FFM are given as kg; ^asignificance of the FFM difference among DXA and different BIA equations methods; ^bPearson correction between BIA equation and DXA values. Abbreviations: BIA: bioelectrical impedance analysis; DXA: dual energy X-ray absorptiometry; FFM: fat free mass.

Figure 1. Bland–Altman plots for hemodialysis patients (A), peritoneal dialysis patients (B) and healthy adults (C) of FFM estimated by BIA-Kyle and DXA methods.

Figure 2. Bland–Altman plots for hemodialysis patients (A), peritoneal dialysis patients (B) and healthy adults (C) of FFM estimated by BIA-Sun ss and DXA methods.

Figure 3. Bland–Altman plots for hemodialysis patients (A), peritoneal dialysis patients (B) and healthy adults (C) of FFM estimated by BIA-Segal and DXA methods.

Figure 4. Bland–Altman plots for hemodialysis patients (A), peritoneal dialysis patients (B) and healthy adults (C) of FFM estimated by BIA-TBW and DXA methods.