Fig. 1

Receiver operating characteristics (ROC) curve for; a baseline forced expiratory volume in 1 s, FEV1%predicted; b forced vital capacity, FVC %predicted; c FEV1/FVC; d angle β; e forced expiratory flow at 50% of FVC, FEF50% %predicted; f forced expiratory flow at 25–75% of FVC, FEF25–75% %predicted in the derivation cohort as predictors of methacholine responsiveness. AUC = Area under the curve. Grey line represents the line of unity with AUC = 0.5