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Table 6 Baseline characteristics of the SP width-stratified classes in negative pre-BPTs

From: Clinical analysis of the “small plateau” sign on the flow-volume curve followed by deep learning automated recognition

Parameter SP sign of negative pre-BPTs
(Vol A − Vol B) × 100/FVC ratio
(≤ 10%)
(N = 50)
(Vol A − Vol B) × 100/FVC ratio
(> 10% to ≤ 20%)
(N = 50)
(Vol A − Vol B) × 100/FVC ratio
(> 20% to ≤ 30%)
(N = 50)
(Vol A − Vol B) × 100/FVC ratio
(> 30%)
(N = 50)
P value
Age, years 39.1 ± 2.2 41.9 ± 2.2 40.6 ± 1.8 37.7 ± 2.0 .797
Sex, n (%)      .002
 Male 31 (62%)c,d 25 (50%) 14 (28%)a 17 (34%)a  
 Female 19 (38%)c,d 25 (50%) 36 (72%)a 33 (66%)a  
BMI, kg/m2 22.4 (19.8, 24.3) 22.4 (19.9, 24.5) 22.4 (20.2, 25.2) 21.3 (20.2, 24.6) .884
Obesity, n (%)
(BMI ≥ 30 kg/m2)
0/50 (0%) 2/50 (4%) 2/50 (4%) 2/50 (4%) .727
Underweight, n (%)
(BMI < 18.5 kg/m2)
5/50 (10%) 5/50 (10%) 5/50 (10%) 5/50 (10%) 1.000
Smoking status, n (%)      .005
 Current or former smoker 17 (34%)d 7 (14%) 5 (10%) 6 (12%)a  
 Never smoker 33 (66%)d 43 (86%) 45 (90%) 44 (88%)a  
FVC % predicted, % 102.5 (95.3, 108.2) 101.7 (92.4, 111.1) 104.1 (98.1, 113.3) 106.3 (95.1, 115.4) .200
FEV1% predicted, % 97.7 (91.9, 103.3)d 98.0 (91.9, 108.0) 102.6 (96.0, 112.5) 105.2 (98.1, 111.4)a .007
FEV1/FVC ratio 0.81 ± 0.01d 0.82 ± 0.01 0.83 ± 0.01 0.85 ± 0.01a .003
Chronic cough, n (%)      < .0001
 Rare 6 (12%)d 11 (22%) 5 (10%) 26 (52%)a  
 Sometimes 44 (88%)d 39 (78%) 45 (90%) 24 (48%)a  
Sputum production, n (%) 24/50 (48%) 24/50 (48%) 22/50 (44%) 24/50 (48%) .971
Chest tightness, n (%) 0/50 (0%) 0/50 (0%) 0/50 (0%) 1/50 (2%) 1.000
Wheezing, n (%) 15/50 (30%) 14/50 (28%) 8/50 (16%) 16/50 (32%) .264
PFT indication, n (%)      
 Asthma 7 (14%) 8 (16%) 6 (12%) 2 (4%) .253
 COPD 10 (20%)d 3 (6%) 0 (0%) 1 (2%)a < .0001
 ILD 0 (0%) 2 (4%) 0 (0%) 0 (0%) .246
 Pulmonary nodule/neoplasia 1 (2%) 2 (4%) 1 (2%) 0 (0%) .903
 Cough 26 (52%) 28 (56%) 28 (56%) 29 (58%) .943
 Shortness of breath 1 (2%) 1 (2%) 2 (4%) 3 (6%) .839
 Rhinitis/sinusitis 5 (10%) 2 (4%) 5 (10%) 2 (4%) .477
 Othere 0 (0%)d 4 (8%) 8 (16%) 13 (26%)a .001
  1. Data are presented as absolute numbers (percentages) in case of frequencies, median values, and quartiles in case of continuous parameters unless otherwise noted. Statistical comparisons based on percent predicted (pp) unless otherwise noted for pulmonary function test (PFT) values
  2. aP < 0.05; (Vol A − Vol B) × 100/FVC ratio ≤ 10% versus the remaining groups 
  3. bP < 0.05; (Vol A − Vol B) × 100/FVC ratio > 10% to ≤ 20% versus the remaining groups
  4. cP < 0.05; (Vol A − Vol B) × 100/FVC ratio > 20% to ≤ 30% versus the remaining groups
  5. dP < 0.05; (Vol A − Vol B) × 100/FVC ratio > 30% versus the remaining groups
  6. eIndications include bronchiectasis, chest pain, pleural effusion, sleep disorder, and studies without documented indication