Lung Sound Analysis Provides A Useful Index For Both Airway Narrowing And Airway Inflammation In Patients With Bronchial Asthma

Figures & data

Table 1 Patient Characteristics And E/I MF Value When Classified Into 4 Groups By Combination Of FEV1 And FeNO

	NN (n=71)	NA (n=29)	AN (n=21)	AA (n=10)
FEV1	N	N	A	A	P-value
FeNO	N	A	N	A	(Pearson)
Male/female, n	18/53	14/15	4/17	4/6	0.074
Age, years	42 (34, 53)	35 (27.5, 60)	53 (33.5, 64.5)	59 (47.5, 67.5)*
BMI, kg/m^2	22.6 (20.3, 25.5)	23.3 (20.1, 24.6)	20.5 (19.1, 21.9)*(#0.06)	20.5 (18.7, 21.9)
Severity; step (1,2,3,4)	25/38/8/0	12/12/4/1	3/10/3/5	0/6/3/1	0.0012
Asthma duration, years	2 (0.7, 6)	7 (1, 17)	8 (1, 21.5)*	13.5 (3.3, 18.5)(*0.07)
History of childhood asthma (no/yes), n	62/9	17/12	17/4	10/0	0.0039
Atopic/non-atopic	37/34	24/5	15/6	4/6	0.0178
Amount of ICS (low/middle/high)	3/67/1	5/22/2	3/13/5	0/9/1	0.0025
Concomitant medicine with ICS (none/montelukast/salmeterol/combination/others)	26/7/7/31/0	18/1/3/7/0	9/0/3/6/3	4/1/3/1/1	0.0075
IgE (IU/mL)	89 (42, 251)	362 (135, 1283)**$	157 (47, 244)	187 (87, 436)
PC20 (µg/mL)	4177 (1250, 7401)	926 (325, 2057)***	754 (356, 2146)**	625 (414, 1472)*
Blood eosinophils, %	5.1 (2.7, 6.8)	9.3 (6.4, 14.6)***	4.4 (2.3, 8.4)	8.3 (6.0, 11.3)*
Sputum eosinophils, %	1 (0, 2)	3.5 (1.5, 6)***	5 (1.5, 16.5)***	10.3 (4, 27.1)***
FEV1/FVC, %	79.9 (76.9, 85.2)	77.9 (75.8, 83.9)	66.8 (60.5, 69.2)	66.3 (63.0, 67.8)
FEV1,%pred, %	100.9 (94.5, 108.2)	98.7 (93.5, 107.5)	79.1 (71.4, 87.6)	88.4 (76.0, 103.5)(*0.08)
V50,%pred, %	79.9 (64.7, 97.5)	66.2 (59.8, 80.4)	37.6 (30.7, 48.6)	41.6 (36.2, 46.2)
V25,%pred, %	57.5 (45.6, 76.6)	54.3 (45.0, 67.2)	28.8 (20.7, 33.3)	31.5 (28.2, 40.6)
E/I MF	0.30 (0.24, 0.41)	0.43 (0.29, 0.61)*	0.52 (0.34, 0.59) **	0.60 (0.41, 0.73) **
FeNO, ppb	20.5 (16.4, 24.1)	61.1 (46.4, 86.4)	23.9 (19.7, 28.2)	79.7 (45.5, 87.2)

Notes: Vs. NN ***p<0.001, **P<0.01, *p<0.05; Vs. NA #: P<0.05; Vs. AN $: P<0.05. The data are indicated by median (25%, 75%). FEV1: A (abnormal); FEV1/FVC <70% or FEV1, %pred <80%, N (normal); FEV1/FVC ≥70% and FEV1,%pred ≥80%. FeNO: A (abnormal); FeNO ≥38ppb, N (normal); FeNO<38ppb. Severity: step 1/2/3/4; mild intermittent/mild persistent/moderate persistent/severe persistent. Amount of ICS (low/middle/high); low; conversion to beclomethasone dipropionate (BDP) ≤400 μg/day, middle; 400–800 μg/day; high; BDP: 800–1600 μg/day, combination; budesonide/formeterol or salmeterol/fluticasone.

Figure 1 Comparison of E/I MF values in four groups classified by combinations of FEV1 and FeNO. FEV1; abnormal (A) cases were defined as FEV1/FVC < 70% or FEV1, %predicted < 80%. Normal (N) cases were defined as FEV1/FVC ≥ 70% and FEV1, %predicted ≥ 80%. FeNO; abnormal (A) cases were defined as FeNO ≥ 38 ppb, whereas normal (N) cases were defined as FeNO < 38 ppb. *p < 0.05, **p < 0. 01.

Table 2 Correlation Between E/I MF And Respiratory Function, FeNO, Sputum Eosinophils

vs. Variable	Spearman Rank Correlation Coefficient (ρ)	p-Value (Prob>|ρ|)
FEV1/FVC (%)	−0.369	<0.0001
FEV1,%pred. (%)	−0.199	0.0229
V50,%pred. (%)	−0.435	<0.0001
V25,%pred. (%)	−0.370	<0.0001
FeNO (ppb)	0.264	0.0024
Sputum eosinophils (%)	0.382	<0.0001

Table 3 Factors Involved In FeNO In FEV1 Normal Groups (group NN And NA) By Multivariate Analysis

	Estimate	SE	t-Value	p-Value	(95% CI)
Sex[F]	−10.04	2.62	−3.83	0.0002	(−15.254,−4.830)
Age (years)	0.21	0.16	1.28	0.2020	(−0.115,0.534)
Ex-smoking (pack-years)	−3.76	1.33	−2.82	0.0058	(−6.412,−1.116)
log IgE	12.16	3.47	3.50	0.0007	(5.267,19.060)
E/I MF	26.82	12.02	2.23	0.0281	(2.945,50.685)

Notes: R²=0.336, analysis of variance<0.001.