Intramuscular and Intermuscular Abdominal Fat Infiltration in COPD: A Propensity Score Matched Study

Figures & data

Figure 1 Distribution of the study subjects and propensity score matching.

Abbreviations: COPD, chronic obstructive pulmonary disease; DBP, diastolic blood pressure; HbA1c, glycosylated hemoglobin; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SBP, systolic blood pressure.

Table 1 Baseline Characteristics of the Study Subjects After Propensity Score Matching

	All Subjects (n = 500)	Control Group (n = 250)	COPD Group (n = 250)	P value^a
Age, years	59.7 ± 7.3	59.7 ± 7.2	59.7 ± 7.4	0.824
Sex, male	492/500 (98.4)	246/250 (98.4)	246/250 (98.4)	0.999
Height, cm	1.7 ± 0.1	1.7 ± 0.1	1.7 ± 0.1	0.752
Weight, kg	69.0 ± 9.9	69.0 ± 9.8	69.1 ± 10.0	0.849
Cardiovascular disease	23/500 (4.6)	10/250 (4.0)	13/250 (5.2)	0.664
Hypertension	155/500 (31.0)	79/250 (31.6)	76/250 (30.4)	0.841
Diabetes	71/500 (14.2)	38/250 (15.2)	33/250 (13.2)	0.620
Hyperlipidemia	26/500 (5.2)	14/250 (5.6)	12/250 (4.8)	0.845
Alcohol consumption				0.728
None	127/500 (25.4)	66/250 (26.4)	61/250 (24.4)
1–2/week	188/500 (37.6)	92/250 (36.8)	96/250 (38.4)
≥ 3/week	185/500 (37.0)	92/250 (36.8)	93/250 (37.2)
Exercise grade				0.959
None	222/500 (44.4)	111/250 (44.4)	111/250 (44.4)
1–2/week	129/500 (25.8)	65/250 (26.0)	64/250 (25.6)
≥ 3/week	149/500 (29.8)	74/250 (29.6)	75/250 (30.0)
SBP, mmHg	125.5 ± 11.1	125.2 ± 11.3	125.7 ± 11.0	0.608
DBP, mmHg	77.8 ± 8.1	77.5 ± 8.6	78.1 ± 7.5	0.348
Total cholesterol, mg/dL	183.0 ± 38.1	182.1 ± 35.3	183.8 ± 40.8	0.616
Triglyceride, mg/dL	121.6 ± 76.9	117.5 ± 82.0	125.6 ± 71.3	0.258
HDL-C, mg/dL	48.8 ± 14.4	48.4 ± 13.5	49.1 ± 15.2	0.588
LDL-C, mg/dL	125.3 ± 35.9	125.5 ± 32.7	125.1 ± 38.9	0.903
Fasting plasma glucose, mg/dL	100.2 ± 24.0	99.9 ± 23.7	100.6 ± 24.4	0.740
HbA1c, %	5.8 ± 1.0	5.8 ± 1.0	5.8 ± 0.9	0.794

Notes: Data are presented as means ± standard deviations or numbers (percentages); ^aStatistical comparisons of the data were performed using the McNemar test or marginal homogeneity test for categorical variables and the paired t-test for continuous variables.

Abbreviations: COPD, chronic obstructive pulmonary disease; DBP, diastolic blood pressure; HbA1c, glycosylated hemoglobin; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SBP, systolic blood pressure.

Figure 2 Distribution of the abdominal body compositions between the control and chronic obstructive pulmonary disease groups in the propensity score matching cohort. (A) Comparison of the attenuations for abdominal fat and muscle, (B) Comparison of the body mass index adjusted cross-sectional areas for abdominal fat and muscle.

Abbreviations: COPD, chronic obstructive pulmonary; HU, Hounsfield units; IMAT, intermuscular adipose tissue; LAMA, low attenuation abdominal muscle area; NAMA, normal attenuation muscle area; SFA, subcutaneous fat area; VFA, visceral fat area.

Table 2 Abdominal Body Fat and Muscle Composition Analysis Results for the Chronic Obstructive Pulmonary Disease Group Compared with the Control Group

	Crude		Adjusted^a		Propensity Score Matched^b
	Unstandardized β (95% CI)	P value^c	Unstandardized β (95% CI)	P value^c	Unstandardized β (95% CI)	P value^c
Attenuation, HU
SFA, HU	0.287 (−0.599, 1.173)	0.525	−0.793 (−1.598, 0.012)	0.053	−1.308 (−2.683, 0.067)	0.062
VFA, HU	−0.398 (−1.444, 0.649)	0.456	−0.066 (−0.900, 0.768)	0.877	−0.320 (−1.800, 1.160)	0.672
IMAT, HU	−0.144 (−0.763, 0.474)	0.648	−0.417 (−1.046, 0.211)	0.193	−0.588 (−1.450, 0.274)	0.181
LAMA, HU	0.700 (0.479, 0.920)	<0.001	0.111 (−0.085, 0.308)	0.266	0.160 (−0.119, 0.439)	0.262
NAMA, HU	−1.783 (−2.288, −1.277)	<0.001	−0.933 (−1.409, −0.457)	< 0.001	−1.168 (−1.803, −0.533)	<0.001
BMI adjusted
SFA index, cm^2/(kg/m^2)	−0.868 (−1.107, −0.630)	<0.001	0.060 (−0.130, 0.249)	0.539	0.056 (−0.204, 0.316)	0.673
VFA index, cm^2/(kg/m^2)	1.116 (0.847, 1.385)	<0.001	0.149 (−0.042, 0.340)	0.126	0.241 (−0.139, 0.620)	0.214
IMAT index, cm^2/(kg/m^2)	0.049 (0.030, 0.069)	<0.001	0.040 (0.021, 0.058)	< 0.001	0.042 (0.012, 0.072)	0.006
LAMA index, cm^2/(kg/m^2)	0.251 (0.207, 0.296)	<0.001	0.113 (0.074, 0.151)	< 0.001	0.120 (0.049, 0.190)	<0.001
NAMA index, cm^2/(kg/m^2)	0.556 (0.406, 0.705)	<0.001	−0.042 (−0.125, 0.041)	0.319	−0.076 (−0.223, 0.072)	0.315

Notes: ^aVariables were adjusted by the propensity score and those with P values less than 0.1 in simple linear regression analysis were included in the multiple linear regression analysis; ^bOf the 6,965 subjects, 250 pairs were matched; ^cStatistical comparisons of the data were performed using simple and multiple linear regression analysis for the entire study cohort and a generalized estimating equations linear regression model for the propensity score matching cohort.

Abbreviations: BMI, body mass index; CI, confidence interval; HU, Hounsfield units; IMAT, intermuscular adipose tissue; SFA, subcutaneous fat area; LAMA, low attenuation abdominal muscle area; NAMA, normal attenuation muscle area; VFA, visceral fat area.

Table 3 Abdominal Body Fat and Muscle Composition Analysis Results for the Chronic Obstructive Pulmonary Disease Subgroups Compared with the Control Group

		Simple		Multiple^a
		Unstandardized β (95% CI)	P value^b	Unstandardized β (95% CI)	P value^b
SFA, HU	Control	Reference		Reference
	Mild COPD	0.755 (−0.600, 2.111)	0.275	−0.154 (−1.352, 1.045)	0.802
	Moderate COPD	−0.032 (−1.209, 1.144)	0.957	−0.634 (−1.677, 0.408)	0.233
VFA, HU	Control	Reference		Reference
	Mild COPD	1.054 (−0.548, 2.657)	0.197	1.287 (0.050, 2.524)	0.041
	Moderate COPD	−1.554 (−2.942, −0.166)	0.028	−0.716 (−1.788, 0.357)	0.191
IMAT, HU	Control	Reference		Reference
	Mild COPD	−0.241 (−1.190, 0.709)	0.619	−0.680 (−1.613, 0.254)	0.154
	Moderate COPD	0.040 (−0.780, 0.860)	0.924	−0.341 (−1.151, 0.468)	0.408
LAMA, HU	Control	Reference		Reference
	Mild COPD	0.767 (0.429, 1.106)	<0.001	0.184 (−0.110, 0.478)	0.219
	Moderate COPD	0.691 (0.399, 0.983)	<0.001	0.044 (−0.210, 0.298)	0.732
NAMA, HU	Control	Reference		Reference
	Mild COPD	−1.596 (−2.373, −0.819)	<0.001	−0.625 (−1.337, 0.087)	0.085
	Moderate COPD	−2.010 (−2.682, −1.338)	<0.001	−1.075 (−1.692, −0.458)	<0.001
SFA index,	Control	Reference		Reference
cm^2/(kg/m^2)	Mild COPD	−1.087 (−1.454, −0.719)	<0.001	−0.090 (−0.373, 0.194)	0.535
	Moderate COPD	−0.689 (−1.007, −0.371)	<0.001	0.242 (−0.004, 0.488)	0.054
VFA index,	Control	Reference		Reference
cm^2/(kg/m^2)	Mild COPD	0.880 (0.468, 1.292)	<0.001	−0.033 (−0.316, 0.251)	0.821
	Moderate COPD	1.317 (0.960, 1.674)	<0.001	0.276 (0.031, 0.522)	0.027
IMAT index,	Control	Reference		Reference
cm^2/(kg/m^2)	Mild COPD	0.043 (0.013, 0.072)	0.004	0.037 (0.009, 0.065)	0.009
	Moderate COPD	0.049 (0.024, 0.075)	<0.001	0.045 (0.020, 0.069)	<0.001
LAMA index,	Control	Reference		Reference
cm^2/(kg/m^2)	Mild COPD	0.221 (0.154, 0.289)	<0.001	0.089 (0.032, 0.147)	0.002
	Moderate COPD	0.279 (0.220, 0.338)	<0.001	0.147 (0.097, 0.197)	<0.001
NAMA index,	Control	Reference		Reference
cm^2/(kg/m^2)	Mild COPD	0.633 (0.403, 0.863)	<0.001	−0.026 (−0.150, 0.097)	0.676
	Moderate COPD	0.529 (0.330, 0.728)	<0.001	−0.133 (−0.240, −0.026)	0.015

Notes: ^aVariables were adjusted by those with P values less than 0.1 in simple linear regression analysis were included in the multiple linear regression analysis; ^bStatistical comparisons of the data were performed using simple and multiple linear regression analysis for the entire study cohort.

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; HU, Hounsfield units; IMAT, intermuscular adipose tissue; SFA, subcutaneous fat area; LAMA, low attenuation abdominal muscle area; NAMA, normal attenuation muscle area; VFA, visceral fat area.