Table 1:

Baseline characteristics of 5594 patients included in the final model

CharacteristicMean ± SD*
Follow-up time, yr9.2 ± 2.9
Baseline age, yr48.4 ± 6.8
Baseline FEV1, L†2.75 ± 0.63
FEV1, % of the predicted value78.47 ± 9.06
Weight, kg75.9 ± 15.1
Height, m1.72 ± 0.09
Methacholine responsiveness (O’Connor slope)‡−12.73 (23.4)
Pack-years of smoking40 ± 19
Sex, no. (%)
Male3524 (63.0)
Female2070 (37.0)
Smoking status by year 5, no. (%)
Sustained quitters951 (17.0)
Intermittent quitters1566 (28.0)
Continuous smokers3077 (55.0)

  • Note: FEV1 = forced expiratory volume in 1 second, SD = standard deviation.

  • ↵* Unless stated otherwise.

  • ↵† After bronchodilator treatment.

  • ↵‡ Unit is change in FEV1 per mg/mL change in methacholine concentration.