Skinfold Anthropometry –The Accurate Method for Fat Free Mass Measurement in COPD

Figures & data

Table 1.  Clinical characteristics of the patient population

		GOLD classification of airflow limitation in COPD (GOLD 1-4)
Anthropometrics	All	1	2	3	4	ANOVA
Age [yrs]	66.5 ± 7.7	68.4 ± 8.9	66.1 ± 7.9	65.7 ± 8.8	67 ± 2.9	0.90
Height [cm]	170.4 ± 8.6	169.6 ± 10.3	173 ± 8.4	165.2 ± 6.1	169.5 ± 7.8	0.12
Weight [kg]	82.1 ± 19.5	87.8 ± 22.1	87.1 ± 16.4	73.2 ± 19.6	71.4 ± 22.4	0.15
BMI [kg·m^−2]	28.2 ± 6.1	30.2 ± 5.6	29.1 ± 5.9	26.8 ± 6.6	24.5 ± 6.1	0.33
OH [l]	0.3 ± 1.08	0.1 ± 0.82	0.46 ± 1.32	0.42 ± 0.87	0.22 ± 0.92	0.55
Pulmonary function
post BDT FEV1 [%]	58.3 ± 19.1	84.7 ± 8.1	64.2 ± 8.0	40.0 ± 5.2	32.8 ± 11.7	< 0.0001
post BDT FEV1/FVC [%]	57.2 ± 13.5	68.9 ± 4.5	61.6 ± 9.2	48.2 ± 12.0	39.0 ± 7.6	< 0.0001
post BDT FEV1/VC [%]	53.3 ± 12.4	64.3 ± 3.5	56.7 ± 8.5	45.8 ± 11.4	36.6 ± 7.1	< 0.0001
6 MWT desaturation [%]	3.4 ± 3.2	2.7 ± 1.6	3.4 ± 3.3	5.1 ± 3.7	1.0 ± 1.4	0.11
6 MWD [m]	391.4 ± 73.7	411.4 ± 56.7	411.3 ± 51.3	374.4 ± 80.5	318.0 ± 115.4	0.06

All values expressed as mean ± SD.

Post BDT FEV₁, forced expiratory volume in 1 second after application of bronchodilator; FVC, forced vital capacity; VC, vital capacity; 6 MWT, 6-minute walk test, 6 MWD, 6-minute walk distance.

Table 2.  Evaluation of body composition with DEXA comparison

		GOLD classification of airflow limitation in COPD (GOLD 1-4)
FFM [kg]	All	1	2	3	4	ANOVA (1-4)
DEXA	60.63 ± 11.66	65.25 ± 15.76	62.76 ± 8.67	54.73 ± 11.45	54.18 ± 13.98	0.17
SFA	59.45 ± 10.56	62.39 ± 13.37	61.03 ± 7.93	55.05 ± 11.84	57.27 ± 13.35	0.45
BIA	56.82 ± 11.40	59.07 ± 16.07	60.13 ± 8.06	49.75 ± 13.38	50.99 ± 7.93	0.11
BIS	51.06 ± 9.925 ***	54.89 ± 11.01	53.88 ± 7.51 **	45.84 ± 11.30	44.36 ± 9.41	0.06
BIA COPD	49.11 ± 9.177 ***	51.21 ± 11.59 *	51.84 ± 7.105 ***	44.62 ± 9.94	43.90 ± 8.52	0.12
FFMI [kg.m^−2]
DEXA	20.65 ± 3.14	22.36 ± 3.44	20.82 ± 2.55	19.95 ± 3.65	18.23 ± 3.46	0.18
SFA	20.42 ± 3.05	21.50 ± 2.93	20.31 ± 2.54	20.18 ± 4.21	19.75 ± 3.22	0.09
BIA	19.34 ± 3.09	20.25 ± 4.00	19.97 ± 2.24	17.87 ± 4.31	17.69 ± 1.89	0.22
BIS	17.50 ± 2.9 ***	18.88 ± 2.25	17.91 ± 2.597 **	16.75 ± 3.64	15.34 ± 2.49	0.15
BIA COPD	16.83 ± 2.578 ***	17.58 ± 2.563 *	17.22 ± 2.301 ***	16.32 ± 3.22	15.18 ± 2.15	0.34
FM [kg]
DEXA	22.89 ± 9.74	23.28 ± 8.88	24.87 ± 10.20	20.51 ± 8.30	17.55 ± 12.24	0.50
SFA	22.68 ± 10.59	25.39 ± 10.96	26.09 ± 10.17	18.16 ± 8.80	14.09 ± 9.38	0.06
BIA	25.59 ± 10.71	28.71 ± 7.54	26.99 ± 11.08	22.38 ± 9.48	20.37 ± 14.48	0.45
BIS	31.08 ± 11.65 **	32.89 ± 13.47	33.24 ± 11.73 **	27.37 ± 8.96	27.00 ± 13.87	0.52
BIA COPD	33.02 ± 11.3 ***	36.56 ± 11.35	35.28 ± 10.69 ***	28.59 ± 10.37	27.46 ± 13.93	0.26
FMI [kg.m^−2]
DEXA	7.84 ± 3.44	8.08 ± 3.06	8.37 ± 3.83	7.44 ± 2.73	5.72 ± 3.65	0.57
SFA	7.76 ± 3.61	8.71 ± 3.56	8.76 ± 3.68	6.59 ± 2.97	4.76 ± 2.97	< 0.0001
BIA	8.77 ± 3.75	9.95 ± 2.40	9.10 ± 4.14	8.06 ± 3.26	6.83 ± 4.45	0.50
BIS	10.65 ± 3.819 **	11.29 ± 4.157 *	11.10 ± 4.09	10.02 ± 3.10	9.14 ± 4.06	0.70
BIA COPD	11.32 ± 3.787 ***	12.58 ± 3.327 ***	11.79 ± 3.978 *	10.45 ± 3.53	9.30 ± 4.05	0.41

All values expressed as mean ± SD. Abbreviations: *, statistical difference between DEXA and each other method (p < 0.05); **, p ≤ 0.001; ***, p < 0.0001; FFM, fat free mass; FFMI, fat free mass index, FM, fat mass; FMI, fat mass index; DEXA, dual energy X-ray absorptiometry, SFA, skin-fold anthropometry, BIA, bioelectrical impedance analysis; BIS, bioimpedance spectroscopy, BIA COPD, bioelectrical impedance analysis with Schols equation.

Figure 1.  Inter-method agreement of FFM measurement and SFA.

Figure 2.  Inter-method agreement of FFM measurement and BIA.

Figure 3.  Inter-method agreement of FFM measurement and BIS.

Figure 4.  IInter-method agreement of FFM measurement and BIA COPD.

Table 3.  Number of patients with identified nutritional depletion via compared methods

	Male FFMI ≤ 16	Female FFMI ≤ 15	Total
DEXA	1	1	2
SFA	1	1	2
BIA	1	3	4
BIS	5	3	8
BIA COPD	5	4	9

FFMI, fat free mass index; DEXA, dual energy X-ray absorptiometry; SFA, skin-fold anthropometry; BIA, bioelectrical impedance analysis; BIS, bioimpedance spectroscopy; BIA COPD, bioelectrical impedance analysis with Schols equation.