A comparison of visual and quantitative methods to identify interstitial lung abnormalities

BMC Pulmonary Medicine

Table 1 Baseline characteristics of COPDGene and Framingham Heart Study (FHS) participants with Interstitial Lung Abnormality (ILA) by identification method

Variable^a	Number (%) or Median (standard deviation) where appropriate
Demographic parameters	COPDGene		FHS
	ILA by Visual Assessment	ILA by HAAs^b	ILA by Visual Assessment	ILA by HAAs^b
	n = 194 (8 %)	n = 26 (1 %)	n = 177 (7 %)	n = 46 (2 %)
Age (years)	64 (10)	62 (8)	70 (12)	65 (13)
Gender (female)	101 (52 %)	14 (54 %)	89 (50 %)	19 (41 %)
Race (African-American)	56 (29 %)	14 (54 %)	-	-
Body Mass Index	28 (7)	33 (4)	28 (5)	32 (5)
Pack years of smoking	44 (27)	42 (26)	26 (20)	18 (15)
Current Smoker	97 (50 %)	18 (69 %)	17 (10 %)	5(11 %)
Spirometric Parameters
FEV₁ (% of predicted)^d	81 % (21)	80 % (32)	98 % (17)	96 % (16)
FVC (% of predicted)^d	88 % (17)	78 % (23)	101 % (15)	96 % (15)
FEV1/FVC %^d	71 % (14)	81 % (18)	97 % (9)	100 % (7)
DLCO (% of predicted)^e	-	-	86 % (14)	86 % (17)
Chest CT parameters
Total Lung Capacity (TLC)^f	5.0 (1.4)	3.5 (1.4)	4.6 (1.2)	3.8 (0.9)
TLC % of predicted^f	95 % (20)	57 % (17)	79 % (17)	64 % (14)

^aData missing in the COPDGene study (n = 2416) for COPD status and pulmonary function testing (n = 1, <1 %) and TLC (n = 19, <1 %). Data missing in the FHS (n = 2633) for spirometry (n = 165, 6 %), diffusion capacity of carbon monoxide (DLCO, n = 572, 22 %), and total lung capacity (n = 192, 7 %)
^bHAAs = High Attenuation Areas (defined by attenuation values between −600 and −250 Hounsfield Units [HUs]) [11]
^cGold Stage ≥ 2 includes those with an FEV₁/FVC % ≥ 0.70, FEV₁ < 80 % of predicted
^dPost-bronchodilator pulmonary function measurements presented. Predicted values for FEV₁ and FVC are derived from Crapo et al. [34]
^eDLCO = Diffusion capacity of carbon monoxide, predicted values are derived from Miller et al. [27]
^fQuantitative metrics of TLC were performed using Airway Inspector (http://airwayinspector.acil-bwh.org). HU: Hounsfield units. Percent of predicted total lung capacity based on ATS/ERS guidelines [35]

ISSN: 1471-2466