Table 3 Spearman’s rank correlation coefficient (ρ/p values) for BMI, LAA% and WA% in patients with COPD

	BMI		LAA%		WA%
	ρ	p Value	ρ	p Value	ρ	p Value
Age (years)	0.040	0.5721	0.050	0.4813	−0.022	0.7802
Smoking Index (pack-years)	−0.027	0.0701	0.092	0.1940	−0.012	0.8772
Height (cm)	−	−	0.092	0.1958	−0.225	0.0037
Weight (kg)	−	−	−0.456	<0.0001	−0.017	0.8255
BSA (m²)	−	−	−0.266	0.0001	−0.094	0.2303
FEV₁ (l/s)	0.280	<0.0001	−0.318	<0.0001	−0.164	0.0356
FEV₁ (%predicted)	0.315	<0.0001	−0.306	<0.0001	−0.176	0.0241
FEV₁/FVC (%)	0.384	<0.0001	−0.495	<0.0001	−0.009	0.9098
RV/TLC (%)	−0.195	0.0057	0.170	0.0159	0.262	0.0007
Tlco (mmol/min/kPa/l)	0.337	<0.0001	−0.642	<0.0001	0.260	0.0007
WA% (%)	0.111	0.156	−0.183	0.0019	−	−
LAA% (%)	−0.557	<0.0001	−	−	−	−

Smoking Index = (the average number of packs smoked/day (20 cigarettes/pack) × years of smoking).
BMI, body mass index; BSA, body surface area; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 s; LAA%, percentage of low attenuation area; RV, residual volume; TLC, total lung capacity; Tlco, carbon monoxide transfer coefficient, bold text indicate significant correlations; WA%, percentage of wall area.