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Table 1 Baseline patient characteristics

From: Dose omission to shorten methacholine challenge testing: clinical consequences of the use of a 10% fall in FEV1 threshold

 

All

BHR present

BHR absent

p

n

208

61

147

 

Age

52 (15)

53 (17)

51 (14)

0.42

Male sex

135 (65)

41 (67)

94 (64)

0.65

BMI

28 (6)

29.2 (6.0)

27.5 (6.0)

0.07

History of asthma

60 (29)

22 (37)

38 (26)

0.11

Atopy

110 (53)

34 (62)

76 (52)

0.23

Pharmacological treatment

 SABA

75 (36)

30 (51)

45 (31)

0.008

 LABA

2 (1)

0 (0)

2 (1)

0.37

 LAMA

7 (3)

4 (7)

3 (2)

0.09

 ICS

51 (25)

18 (31)

33 (23)

0.25

 ICS–LABA combination

34 (16)

9 (15)

35 (17)

0.73

Lung function testinga

 FEV1/FVC

0.76 (0.07)

0.73 (0.09)

0.79 (0.06)

< 0.001

 FEV1, l

2.82 (0.77)

2.55 (0.81)

2.95 (0.72)

0.001

 FEV1, %

95 (14)

90 (15)

98 (13)

< 0.001

 FVC, l

3.66 (0.95)

3.45 (98)

3.76 (0.92)

0.04

 FVC, %

97 (13)

96 (14)

98 (12)

0.24

 RV, l

1.86 (0.57)

2.01 (0.70)

1.79 (0.49)

0.02

 RV, %

100 (25)

111 (33)

96 (19)

< 0.001

 FRC, l

2.85 (0.68)

2.88 (0.75)

2.83 (0.65)

0.66

 FRC, %

96 (19)

100 (23)

94 (16)

0.07

 TLC, l

5.61 (1.03)

5.56 (1.00)

5.63 (1.04)

0.70

 TLC, %

102 (13)

104 (14)

102 (12)

0.27

 DLCO, %

94 (19)

92 (24)

96 (17)

0.24

Methacholine challenge

 Starting dose, mg/ml

1 (0.25–1)

1 (0.25–1)

1 (1–1)

0.001

 PC20, mg/mlb

4.2 (1.5–6.8)

2.2 (1.1–5.3)

12.3 (10.0–14.1)

< 0.001

  1. Data presented as mean (standard deviation), median (interquartile range) or n (percent), where appropriate
  2. BHR is considered present when CP20 is ≤ 8 mg/ml
  3. BHR bronchial hyperresponsiveness, BMI body mass index, SABA short-acting beta-agonist, LABA long-acting beta-agonist, LAMA long-acting muscarinic antagonist, ICS inhaled corticosteroid, FEV1 forced expiratory volume in 1 s, FVC forced vital capacity, RV residual volume, FRC functional residual capacity, TLC total lung capacity, DLCO diffusion capacity of the lung for carbon monoxide
  4. aData available for 186 patients
  5. bMean for the “BHR absent” group based on 16 patients. PC20 was > 16 mg/ml in the remaining 131 patients