Imaging-based clusters in current smokers of the COPD cohort associate with clinical characteristics: the SubPopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS)

Table 3 Demography, baseline (Pre-bronchodilator) and maximal (Post-bronchodilator) PFTs, in four imaging-based clusters

	Cluster 1	Cluster 2	Cluster 3	Cluster 4	P value
	N = 96	N = 45	N = 88	N = 55
Demography
GOLD stages (%) (0/1/2/3/4)	68/22/10/0/0	47/11/33/9/0	27/15/51/7/0	4/2/40/47/7	< 0.0001
ABCD assessment (%) (A/B/C/D)	37/47/1/14	25/52/0/22	35/49/0/16	10/51/0/39	= 0.0005
Strata (%) (2/3/4)	68/32/0	51/40/9	27/66/7	4/44/52	< 0.0001
Gender (Female %)	44	49	44	31	0.26
Race (White/Black/Others)	60/32/7	36/58/7	72/26/2	80/15/5	0.0001
Age (yrs.)	54.44 (8.01)	56.76 (8.51)	61.01 (8.24)	64.47 (8.14)	< 0.0001
BMI (kg/m2)	27.63 (4.7)	31.1 (5.04)	25.58 (4.76)	23.65 (4.26)	< 0.0001
BODE index	0.48 (0.9)	1.4 (1.9)	0.98 (1.1)	2.94 (1.7)	< 0.0001
Pre-bronchodilator values^a
FEV1% predicted	0.91 (0.17)	0.73 (0.22)	0.68 (0.2)	0.42 (0.17)	< 0.0001
FVC % predicted	1.01 (0.15)	0.86 (0.17)	0.86 (0.18)	0.74 (0.16)	< 0.0001
FEV1/FVC	0.71 (0.09)	0.66 (0.14)	0.61 (0.1)	0.43 (0.11)	< 0.0001
Post-bronchodilator values^b
FEV1% predicted	0.97 (0.16)	0.8 (0.2)	0.76 (0.18)	0.49 (0.17)	< 0.0001
FVC % predicted	1.04 (0.15)	0.92 (0.16)	0.93 (0.17)	0.85 (0.16)	< 0.0001
FEV1/FVC	0.74 (0.09)	0.68 (0.13)	0.63 (0.11)	0.44 (0.12)	< 0.0001

Data presented as number (%) or mean (SD). ANOVA and chi-square tests were performed for continuous and categorical variables, respectively. ^aPre-bronchodilator values. ^bPost-bronchodilator values after six to eight puffs of albuterol. Full names of each variable were described in Abbreviations used. BODE indexes for 8 subjects were not available

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