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Table 1 Baseline characteristics of IPF participants

From: A role for cardiopulmonary exercise testing in detecting physiological changes underlying health status in Idiopathic pulmonary fibrosis: a feasibility study

Characteristic

Overall n = 27

Mild n = 19

Moderate n = 8

p value

Age (years) (mean, SD)

75 (± 6.0)

75 (± 6.6)

74 (± 4.3)

0.440

Gender (male n, %)

22, 82%

14, 74%

8, 100%

0.280

Smoking history (n, %)

    

 Current

0, 0%

0, 0%

0, 0%

0.552

 Never

10, 37%

9, 47%

1, 12.5%

 

 Ex-smoker

17, 63%

10, 53%

7, 87.5%

 

BMI (kg/m2) (mean, SD)

28.5 (± 4.5)

28.9 (± 5.0)

27.7 (± 2.9)

0.585

MRC (n)

   

0.964

 0–1

4

3

1

 

 2

16

11

5

 

 3

7

5

2

 

 4–5

0

0

0

 

Antifibrotics (n,%)

9, 33%

5, 26%

4, 50%

0.375

Co-morbidities

   

n/s

 Gastro-oesophageal reflux

11

6

5

 

 Hypertension

10

7

3

 

 Coronary artery disease

10

4

6

 

 Diabetes

3

1

2

 

Lung function parameters (mean, SD)

    

FVC (L)

2.96 (± 0.72)

3.11 (± 0.78)

2.61 (± 0.46)

0.050

FVC (% predicted)

91 (± 16.0)

99 (± 10.0)

70 (± 5.1)

 < 0.0001

FEV1/FVC ratio

78 (± 7.9)

76 (± 7.8)

82 (± 7.2)

0.080

TLco % predicted

61 (± 9.0)

63 (± 9.5)

57 (± 6.2)

0.055

6MWT (mean, SD)

n = 25

n = 18

n = 7

 

Distance achieved (m)

350 (± 63.3)

349 (± 66.6)

354 (± 58.6)

0.827

% theoretical distance (m)

78 (± 16.3)

78 (± 16.5)

76 (± 17.0)

0.821

CPET (mean, SD)

n = 27

n = 19

n = 8

 

VO2 peak/kg (ml/kg/min)*

20.9 (± 3.9)

20.6 (± 4.2)

21.7 (± 3.1)

0.489

VO2/kg at AT (ml/kg/min)

13.6 (± 3.5)

13.8 (± 3.6)

13.0 (± 3.2)

0.585

VE peak (L/min)

69.9 (± 21.1)

69.0 (± 21.7)

72.1 (± 20.9)

0.731

VE peak (% predicted)

74.5 (± 14.4)

71.0 (± 13.9)

82.9 (± 12.4)

0.045

VE/VCO2 at AT

28.2 (± 3.1)

28.7 (± 3.3)

27.2 (± 2.4)

0.201

Minimum O2 saturation during CPET(%)

91 (± 4.7)

91 (± 5.4)

92 (± 2.8)

0.723

Peak work rate (W)

104.8 (± 26.4)

103.6 (± 29.4)

107.6 (± 18.7)

0.673

Peak work (% predicted)

44 (± 8.6)

44 (± 9.5)

43 (± 6.1)

0.565

HR (bpm)

141 (± 21.8)

141 (± 21.2)

139 (± 24.5)

0.793

HR (% predicted)

97 (± 15.1)

98 (± 15.0)

95 (± 16.2)

0.711

BR max (L/min); median (IQR)

26.5 (18.4–32.5)

28.8 (18.8–33.3)

20.4 (12–24.9), n = 7

0.083

K-BILD questionnaire (mean, SD)

n = 27

n = 19

n = 8

 

 Total

65 (± 9.7)

67 (± 10.3)

60 (± 6.6)

0.058

 Psychological domain

69 (± 17.8)

72 (± 17.8)

61 (± 15.7)

0.128

 Breathlessness and activity domain

56 (± 12.6)

57 (± 13.6)

52 (± 9.4)

0.267

 Chest symptoms domain

78 (± 17.7)

81 (± 18.2)

71 (± 14.6)

0.133

IPF-PROM questionnaire (mean, SD)

n = 27

n = 19

n = 8

 

 Total

20 (± 4.3)

20 (± 4.6)

21 (± 3.5)

0.337

 Physical breathlessness

5 (± 1.5)

5 (± 1.4)

5 (± 1.5)

0.264

 Psychological breathlessness

5 (± 1.3)

5 (± 1.2)

6 (± 1.5)

0.121

 Well-being

5 (± 2.0)

5 (± 2.2)

5 (± 1.3)

0.662

 Energy

5 (± 1.5)

5 (± 1.7)

5 (± 0.8)

0.565

VAS Cough (cm) (median, (IQR))

1.7 (0.8–2.8)

1.5 (0.2–2.6)

2.3 (1.4–3.0)

0.135

Bristol VAS breathlessness (cm)

1.9 (0.8–3.3)

1.8 (0.8–3.4)

2.4 (1.1–4.7)

0.630

Bristol VAS fatigue (cm)

3.7 (1.1–5.1)

3.7 (1.1–5.1)

3.8 (1.4–6.3)

0.457

  1. All data shown as mean with standard deviation(SD) unless otherwise stated. All visual analogue scores presented as median with interquartile range (IQR). *Referenced VO2 peak/kg for a 75 year old man would be 26.5 ml/kg/min (based on the linear regression equation male =  − 0.42 × age(years) + 58 (Schneider, Lung 2013 [28]). years years; SD standard deviation; n number; % percentage; FVC forced vital capacity; L litres; FEV1 forced expiratory volume in one second, TLco transfer factor; m metres, HR heart rate; MRC medical research council dyspnoea score; VAS visual analogue score; cm centimetres; bpm beats per minute; W Work; O2 oxygen; L litres; 6MWT 6 min walk test; BMI body mass index; CPET cardiopulmonary exercise test; K-BILD King’s Brief interstitial lung disease questionnaire; IPF-PROM idiopathic pulmonary fibrosis patient reported outcome measure. Unpaired t-test with Welch’s correction was used to compare parametric data of mild and moderate groups, whilst Mann Whitney u was used for non-parametric data. Fisher’s exact test was used to compare categorical data. A p < 0.05 was considered statistically significant
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BMC Pulmonary Medicine

ISSN: 1471-2466

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