AUC | 95% CI | Cut-off value | False-positive rate % | p-value | |

MEF_{75} % pred | 0.91 | 0.79–1.01 | <31 | 9 | 0.01 |

FEV_{1} % pred | 0.89 | 0.77–1.01 | <48 | 9 | 0.01 |

Tiffeneau index^{¶} | 0.89 | 0.76–1.10 | <56 | 9 | 0.01 |

MEF_{25} % pred | 0.84 | 0.70–0.98 | <13.5 | 17 | 0.004 |

P_{a,O2} baseline kPa | 0.86 | 0.71–1.00 | <9.5 | 23 | 0.004 |

S_{a,O2} baseline % | 0.85 | 0.71–1.00 | <94 | 28 | 0.03 |

P_{a,O2} after HIT kPa | 0.80 | 0.58–1.00 | <6.8 | 33 | 0.02 |

The cut-off values and false-positive rates correspond to a sensitivity of ≥75%. AUC: area under curve; CI: confidence interval; MEF

_{75}: maximal expiratory flow when 75% of the forced vital capacity (FVC) remains to be exhaled; FEV_{1}: forced expiratory volume in one second; MEF_{25}: maximal expiratory flow when 25% of the FVC remains to be exhaled;*S*_{a,O2}: arterial oxygen saturation; HIT: hypoxia inhalation test; % pred: percentage of the predicted value.^{#}: the greater the AUC the better the predictive value of the baseline parameter (see fig. 1⇑); for example, in the present population, six of 36 (sensitivity 84%) patients with an FEV_{1}of <48% pred showed resting*P*_{a,O2}at altitude of <6.6 kPa, whereas three of 36 patients (8.6%) showed*P*_{a,O2}of >6.6 kPa;^{¶}; FEV_{1}/FVC.