Table 2

Characteristics of subjects stratified by airway obstruction and reversibility at visit 2 (n=225)

No airway obstruction (NAO)Reversible airway obstruction (RAO)Irreversible airway obstruction (IAO)
BHR=bronchial hyperresponsiveness; FEV1=forced expiratory volume in 1 second; Kco=carbon monoxide transfer coefficient; bd=bronchodilator; NAO=FEV1 pre-bd ≥80% predicted; RAO=FEV1 pre-bd <80% predicted and reversibility ≥9% predicted: IAO=FEV1 pre-bd <80% predicted and reversibility <9% predicted. *p<0.05, NAO v RAO; †p<0.05, NAO v IAO; ‡p<0.05, RAO v IAO.
n939735
Median (range) age at visit 1 (years)19 (13–39)*†27 (13–44)*27 (13–44)†
Sex (% male)53.861.960.0
Median (range) age of onset of asthma (years)5 (0–36)4 (0–37)4 (0–39)
Median (range) untreated period (years)12 (0–36)*†15 (0–42)*19 (0–42)†
Smoking visit 1, non/ex/current (%)54.8/11.8/33.354.6/7.2/38.154.3/2.9/42.9
Smoking visit 2, non/ex/current (%)38.7/30.1/31.242.3/35.1/22.740.0/31.4/28.6
Median (range) pack years smoking at visit 23.0 (0–37)2.5 (0–80)4.5 (0–56)
≥1 positive skin test at visit 1 (%)96.892.891.4
≥1 positive skin test at visit 2 (%)89.2†80.474.3†
Geometric mean (SD) IgE at visit 2 (IU)89.1 (3.5)97.7 (4.5)67.6 (4.7)
Geometric mean (SD) slope BHR at visit 15.4 (3.3)*9.7 (3.3)*6.4 (3.8)
Geometric mean (SD) slope BHR at visit 21.8 (4.6)*†9.8 (3.2)*‡3.9 (3.4)†‡
BHR ≤4 mg/ml at visit 1 (%)47.3*64.9*51.4
BHR ≤32 mg/ml at visit 2 (%)69.9*†98.7*92.9†
BHR ≤4 mg/ml at visit 2 (%)31.2*80.3*‡42.9‡
Mean (SD) FEV1 pre-bd at visit 1 (% pred)76.7 (21.1)*†55.2 (19.3)*48.6 (18.3)†
Mean (SD) FEV1 post-bd at visit 1 (% pred)98.3 (16.6)*†84.2 (19.2)*‡72.7 (19.6)†‡
Mean (SD) FEV1 pre-bd at visit 2 (% pred)93.6 (9.9)*†55.5 (15.3)*54.7 (19.0)†
Mean (SD) FEV1 post-bd at visit 2 (% pred)103.3 (9.8)*†73.1 (15.6)*‡60.0 (19.1)†‡
Mean (SD) FEV1 reversibility at visit 1 (% pred)21.6 (13.8)*29.0 (11.8)*‡24.1 (11.2)‡
Mean (SD) FEV1 reversibility at visit 2 (% pred)9.7 (6.1)*†17.7 (6.3)*‡5.3 (3.0)†‡
Mean (SD) FEV1 % IVC pre-bd at visit 1 (%)63.2 (15.4)*†48.2 (14.3)*46.3 (15.4)†
Mean (SD) FEV1 % IVC post-bd at visit 1 (%)77.2 (11.6)*†67.7 (13.6)*‡61.9 (16.5)†‡
Mean (SD) FEV1 % IVC pre-bd at visit 2 (%)71.6 (7.3)*†52.0 (11.0)*54.8 (14.3)†
Mean (SD) FEV1 % IVC post-bd at visit 2 (%)75.4 (6.9)*†59.1 (11.2)*55.5 (15.4)†
Pulmonary medication use at visit 2 (%)41.9*†88.7*‡74.3†‡
Inhaled corticosteroid use at visit 2 (%)24.7*†72.2*‡51.4†‡
Oral corticosteroid use at visit 2 (%)1.1*†10.3*17.1†
Reduced Kco post-bd at visit 2 (%)21.120.336.0