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Table 4 Description of lung function, sensitisation and health-care utilisation

From: Frequent cough in unsatisfactory controlled asthma – results from the population-based West Sweden Asthma Study

Variables

No

Current asthma

No

Controls

P values

Overall number of subjects

744

 

847

  

FEV1% predicted

707

90.6 ± 17.6

816

101.0 ± 12.9

<0.001

FEV1% predicted below 80%

707

164 (23.2)

816

43 (5.3)

<0.001

Positive reversibility after a bronchodilator

444

110 (24.8)

465

16 (3.4)

<0.001

FEV1/FVC ratio < 0.7

705

96 (13.6)

817

33 (4.0)

<0.001

FeNO ppb#

597

26.88 ± 24.3

676

19.03 ± 11.0

<0.001

Reactiveness to PD20 ≤ 1.96 mg**

275

195 (70.9)

328

105 (32.0)

<0.001

At least 1 positive SPT

575

413 (71.8)

577

191 (33.1)

<0.001

Number of positive SPT in the sensitised subjects

413

 

191

  

    1

 

79 (19.1)

 

68 (35.6)

<0.001*

    2

 

63 (15.3)

 

54 (28.3)

    3

 

75 (18.2)

 

29 (15.2)

    ≥4

 

196 (47.4)

 

40 (20.9)

Doctor's office visits

740

263 (35.3)

844

80 (9.5)

<0.001

Hospitalisations

735

16 (2.2)

844

1 (0.1)

<0.001

Emergency visits due to respiratory problems

733

78 (10.6)

842

11 (1.3)

<0.001

  1. Comparisons of FEV1/FVC ratio, PD20 reactiveness, positive reversibility after a bronchodilator and BMI are done using Chi-square test, other clinical parameters are compared using unpaired t-test. *p-value from the test for trend.
  2. #measured at 50 ml/s.
  3. **% of subjects reacted to methacholine dose ≤ of 1.96 mg with 20% fall in the FEV1.
  4. Data are presented as number of subjects No (%) or mean ± SD.