Dean James, Beech Augusta, Singh Dave
Division of Immunology, Immunity to infection and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester and Manchester University NHS Foundation Trust, Manchester, UK.
Medicines Evaluation Unit, Southmoor Road, Manchester, M23 9QZ, UK.
Lung. 2025 Jul 5;203(1):73. doi: 10.1007/s00408-025-00823-5.
The methacholine challenge requires a 20% fall in forced expiratory volume in one second (FEV). The fall is measured as litre (L) change from the pre-challenge (baseline) value. A higher baseline FEV requires a greater volume change to reach a 20% fall. The aim of this study was to evaluate change using percent predicted, which may remove dependence on the baseline value.
Challenge data from a cohort of 114 asthma patients was re-analysed. The dose causing an 20% fall from baseline (PD) was compared to a 15% fall in predicted value (PD) for the classification of bronchial hyperresponsiveness.
There was significant agreement between PD and PD (r = 0.95, p < 0.0001), with an ICC of 0.97. PD was significantly higher than PD (0.0055 mg, p < 0.0001). Greater decreases in FEV were observed with PD versus PD (21.4% pred vs 19.1% pred respectively, p = 0.0004), with 29% of patients requiring at least one additional dose of methacholine to achieve PD compared to PD. A higher baseline FEV resulted in higher PD values, whereas no relationship was found for PD. Variability in FEV between repeated visits (n = 15) was associated with the change in PD, but not the change in PD.
We suggest a PD criteria based on 15% predicted change should be used for bronchial challenge testing. This method is less influenced by baseline airflow obstruction, and is a more efficient and safer way of measuring airway hyperresponsiveness.
乙酰甲胆碱激发试验要求一秒用力呼气容积（FEV）下降20%。下降幅度以相对于激发前（基线）值的升（L）变化来衡量。较高的基线FEV需要更大的容积变化才能达到20%的下降幅度。本研究的目的是使用预测百分比来评估变化，这可能消除对基线值的依赖。
对一组114例哮喘患者的激发试验数据进行重新分析。将导致从基线下降20%的剂量（PD）与预测值下降15%的剂量（PD）进行比较，以对支气管高反应性进行分类。
PD与PD之间存在显著一致性（r = 0.95，p < 0.0001），组内相关系数为0.97。PD显著高于PD（0.0055毫克，p < 0.0001）。与PD相比，PD时观察到FEV有更大幅度下降（分别为预测值的21.4%对19.1%，p = 0.0004），与PD相比，29%的患者需要至少额外一剂乙酰甲胆碱才能达到PD。较高的基线FEV导致更高的PD值，而PD未发现相关性。重复就诊（n = 15）时FEV的变异性与PD的变化相关，但与PD的变化无关。
我们建议基于预测变化15%的PD标准应用于支气管激发试验。该方法受基线气流阻塞的影响较小，是一种更有效、更安全的测量气道高反应性的方法。
