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Table 1 Baseline characteristics of the study population

From: Lung hyperinflation and functional exercise capacity in patients with COPD – a three-year longitudinal study

Predictors

Total

Female

Male

P-value

Sex, n (%)

389 (100)

153 (39.3)

236 (60.7)

 

Age (years)

63.6 ± 6.8

62.6 ± 6.3

64.2 ± 7.0

0.028

6MWD (m)

423 ± 112

406 ± 104

434 ± 115

0.015

SpO2 before 6MWT (%)

94.2 ± 2.7

94.1 ± 2.9

94.3 ± 2.6

0.621

SpO2 after 6MWT (%)

91.0 ± 5.7

90.9 ± 6.1

91.0 ± 5.4

0.804

Borg dyspnea score after 6MWT (median)

4.0

4.0

3.0

0.085

mMRC

2.2 ± 2.3

2.3 ± 2.4

2.1 ± 2.2

0.410

BMI (kg/m2)

25.4 ± 5.2

24.5 ± 5.7

25.9 ± 4.8

0.016

FMI (kg/m2)

8.4 ± 3.3

9.8 ± 3.7

7.4 ± 2.6

< 0.001

FFMI (kg/m2)

17.0 ± 3.2

14.7 ± 2.4

18.5 ± 2.8

< 0.001

Smoking status n (%)

   

0.215

 Current

167 (43)

72 (47)

95 (40)

 

 Former

222 (57)

81 (53)

141 (60)

 

Pack years

40.9 ± 22.8

33.5 ± 16.6

45.6 ± 24.9

< 0.001

GOLD category, n %

   

0.283

 II

179 (46)

76 (50)

103 (44)

 

 III

169 (43)

65 (42)

104 (44)

 

 IV

41 (11)

12 (8)

29 (12)

 

Charlson comorbidity index, n (%)

   

0.011

 1

225 (58)

99 (65)

126 (53)

 

 2

93 (24)

38 (25)

55 (23)

 

 3

46 (12)

12 (8)

34 (15)

 

 4

25 (6)

4 (2)

21 (9)

 

Experienced > 2 exacerbations, n (%)

75 (20)

38 (25)

37 (16)

0.036

FEV1 (L)

1.5 ± 0.5

1.3 ± 0.4

1.7 ± 0.5

< 0.001

FEV1 (% pred.)

48.7 ± 14.0

49.6 ± 13.5

48.1 ± 14.4

0.315

FVC (L)

3.3 ± 0.9

2.7 ± 0.6

3.7 ± 0.8

< 0.001

FVC (% pred.)

85.5 ± 16.6

85.2 ± 17.1

85.6 ± 16.4

0.791

FEV1/FVC (%)

45.7 ± 11.1

47.6 ± 11.0

44.5 ± 11.0

0.006

TLC (L)

7.1 ± 1.4

6.1 ± 0.9

7.8 ± 1.3

< 0.001

TLC (% pred.)

115.9 ± 18.0

121.4 ± 17.8

112.3 ± 17.1

< 0.001

IC (L)

2.4 ± 0.7

2.0 ± 0.5

2.7 ± 0.7

< 0.001

IC/TLC ratio

0.35 ± 0.09

0.36 ± 0.08

0.33 ± 0.09

0.002

TLCO

5.2 ± 1.9

4.4 ± 1.6

5.6 ± 2.0

< 0.001

TLCO (% pred.)

59.1 ± 18.8

57.2 ± 18.5

60.3 ± 19.0

0.143

Physical activity ≥1 h/week

 Light physical activity

263 (73.0)

104 (73.7)

159 (72.6)

0.691

 Hard physical activity

141 (39.6)

54 (38.9)

88 (40.6)

0.139

  1. Data are presented as mean ± SD, unless otherwise stated. Independent samples T-test for continuous variables and Chi square for categorical variables
  2. 6MWD 6-min walking distance, BMI body mass index, FMI fat mass index, FFMI fat free mass index, GOLD Global Initiative for Chronic Obstructive Lung Disease, FEV1 forced expiratory volume in 1 s, FVC forced vital capacity, IC inspiratory capacity, TLC total lung capacity, IC/TLC ratio inspiratory-to-total lung capacity ratio, TLCO transfer factor for carbon monoxide