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Table 1 Baseline and clinical characteristics of the study population

From: Distinct risks of exacerbation and lung function decline between never-smokers and ever-smokers with COPD

 

Never-smoker COPD (n = 75)

Ever-smoker COPD (n = 508)

P-value

Follow-up duration, year

5.9 ± 3.8

5.2 ± 3.2

0.149*

Age, years

64.8 ± 11.3

66.4 ± 9.1

0.259*

Female sex, n (%)

38 (50.7)

17 (3.3)

< 0.001†

Body mass index, kg/m2

22.3 ± 3.2

22.3 ± 3.4

0.778*

Smoking intensity, pack-years

0 ± 0

42.4 ± 23.7

< 0.001*

Charlson comorbidity index

1.53 ± 1.02

1.56 ± 1.05

0.701*

History of tuberculosis, n (%)

33 (44)

122 (24)

< 0.001†

History of NTM lung disease, n (%)

3 (4)

6 (1.2)

0.065†

Physician-diagnosed asthma, n (%)

28 (37.3)

124 (24.4)

0.017†

Baseline lung function

   

 FEV1, L

1.4 ± 0.5

1.7 ± 0.6

< 0.001*

 FEV1, % predicted

62.3 ± 18

66.5 ± 19

0.059*

 FVC, L

2.5 ± 0.7

3.3 ± 0.8

< 0.001*

 FVC % predicted

78.8 ± 17.2

89.6 ± 17.7

< 0.001*

 FEV1/FVC, %

55.3 ± 10

51.4 ± 11.6

0.007*

 FEF25%–75%, % predicted

24.9 ± 9.8

27.9 ± 11.6

0.039*

 DLCO, mL/mmHg/min

14.2 ± 4.1

13.5 ± 4.3

0.131*

 DLCO, % predicted

85.6 ± 22.7

81.1 ± 21.2

0.033*

 Positive bronchodilator response, n (%)

1 (1.3)

68 (13.4)

0.003†

Laboratory findings

   

 Blood neutrophil-to-lymphocyte ratio

4.6 ± 9.2

3.6 ± 3.6

0.286*

 Blood eosinophil count, × 103/L

221.6 ± 274.8

224.8 ± 234

0.408*

 Blood eosinophil count of > 300 × 103/L, n (%)

14 (18.7)

113 (22.2)

0.484†

Baseline CT findings

   

 Emphysema, n (%)

15 (20)

406 (79.9)

< 0.001†

 Tuberculosis-destroyed lung, n (%)

18 (24)

41 (8.1)

< 0.001†

 Bronchiectasis, n (%)

52 (69.3)

226 (44.5)

< 0.001†

 Interstitial lung disease, n (%)

1 (1.3)

13 (2.6)

0.518†

Inhaler use, n (%)

74 (98.7)

467 (91.9)

0.035†

Inhaler medication possession ratio

0.7 ± 0.3

0.6 ± 0.4

0.421*

  1. Data are presented as mean ± standard deviation or n (%)
  2. *P-values were calculated using the t-test for continuous variables
  3. †P-values were calculated using the chi-square test (or Fisher’s exact test where applicable) for categorical variables
  4. COPD = chronic obstructive pulmonary disease; CT = computed tomography; DLCO = diffusing capacity of the lungs for carbon monoxide; FEF25%–75% = forced expiratory flow between 25% and 75% of vital capacity; FEV1 = forced expiratory volume in 1 s; FVC = forced vital capacity; NTM = nontuberculous mycobacteria
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BMC Pulmonary Medicine

ISSN: 1471-2466

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