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Table 2 Comparison of demographics and baseline spirometry parameters in patients with positive versus negative methacholine challenge test in the derivation cohort

From: Baseline spirometry parameters as predictors of airway hyperreactivity in adults with suspected asthma

 

Methacholine negative (n = 1932)

Methacholine positive (n = 305)

P value

Mean

SD

Mean

SD

Age (years)

24.10

3.65

24.50

3.80

0.16

Females

367 (19%)

–

67 (22%)

–

0.22*

Height (cm)

173.60

8.29

172.89

9.16

0.18

Weight (kg)

69.53

12.26

68.77

13.50

0.36

BMI (kg/m2)

23.01

3.44

22.80

3.46

0.56

Smoking n (%)**

    

0.26

 Non-smoker

176 (67)

 

42 (67)

  

 Ex-smoker

12 (5)

 

6 (9)

  

 Smoker

75 (28)

 

15 (24)

  

 Total

263 (100)

 

63 (100)

  

FEV1/FVC ratio (%pred)

84.10

7.40

80.10

7.50

 < 0.01

FEV1 (%pred)

95.40

11.00

89.10

11.70

 < 0.01

FEF50% (%pred)

89.80

22.80

75.10

18.00

 < 0.01

FVC (%pred)

99.50

13.00

96.50

13.00

 < 0.01

FEF25–75% (%pred)

86.90

23.10

82.70

22.80

 < 0.01

angle β (°)

186.96

15.01

180.92

12.36

 < 0.01

  1. Methacholine positive defined as PC20 ≤ 16 mg/ml; PC20, Concentration of methacholine causing a 20% decrease in FEV1. BMI, Body Mass Index; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; FEF50%, forced expiratory flow at 50% of FVC; FEF25–75%, forced expiratory flow at 25–75% of FVC; Relative values of spirometry parameters are given as percentage of the predicted value (% pred)
  2. *P value from Chi-squared analysis
  3. **Smoking status was available for 326 patients in the derivation cohort—263 from the MCT negative patients and 63 from the MCT positive patients
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BMC Pulmonary Medicine

ISSN: 1471-2466

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