Louis Renaud, Bougard Nicolas, Guissard Françoise, Paulus Virginie, Henket Monique, Schleich Florence
Department of Pneumology, CHU Liege, GIGA I(3) Research Group, University of Liege, Liege, Belgium.
Department of Pneumology, CHU Liege, GIGA I(3) Research Group, University of Liege, Liege, Belgium.
J Allergy Clin Immunol Pract. 2020 Feb;8(2):618-625.e8. doi: 10.1016/j.jaip.2019.09.007. Epub 2019 Sep 18.
Methacholine bronchial challenge and bronchodilation to salbutamol are key tests in clinical practice to make asthma diagnosis.
To assess the concordance between the 2 tests and to see whether they actually identify the same population of asthmatics.
We conducted a retrospective study using our asthma clinic database to see how methacholine bronchial challenge compared to bronchodilation to salbutamol in untreated patients with recurrent or chronic symptoms suspicious of asthma. We identified 194 untreated patients with baseline forced expiratory volume in 1 second (FEV) ≥70% predicted who had both a bronchodilation test with salbutamol and a methacholine bronchial challenge 7 to 14 days apart. A positive bronchial challenge was a provocative concentration of methacholine causing a 20% fall in FEV ≤16 mg/mL, whereas a positive bronchodilation test was a reversibility to 400 μg inhaled salbutamol ≥12% from baseline and 200 mL.
Overall, asthma diagnosis was confirmed in 91% of cases leaving 9% of subjects with double negative tests. Isolated positive methacholine challenge was found in 71% of subjects, double positive tests in 17%, whereas isolated significant bronchodilation to salbutamol was rare (3%). There was no correlation between provocative concentration of methacholine causing a fall in FEV of 20% (PC20M) and the magnitude of salbutamol reversibility (P = .10). Baseline FEV/forced vital capacity ratio inversely correlated with reversibility to salbutamol (P < .001) but not with PC20M (P = .1). No difference was found between the groups regarding demographic and immunoinflammatory features, including the proportion of eosinophilic asthma.
We conclude that methacholine challenge outperforms reversibility to salbutamol to diagnose asthma without selecting patients with distinct inflammatory profile. Baseline airway obstruction predicts magnitude of reversibility but not hyperresponsiveness.
乙酰甲胆碱支气管激发试验和沙丁胺醇支气管舒张试验是临床实践中用于哮喘诊断的关键检查。
评估这两项检查之间的一致性，并观察它们是否真的能识别出相同的哮喘患者群体。
我们使用哮喘门诊数据库进行了一项回顾性研究，以比较乙酰甲胆碱支气管激发试验与沙丁胺醇支气管舒张试验在未经治疗的、有复发或慢性症状且怀疑哮喘的患者中的情况。我们确定了194例未经治疗的患者，其基线第1秒用力呼气容积（FEV）≥预计值的70%，这些患者在7至14天内分别进行了沙丁胺醇支气管舒张试验和乙酰甲胆碱支气管激发试验。支气管激发试验阳性是指乙酰甲胆碱激发浓度导致FEV下降20%且激发浓度≤16 mg/mL，而支气管舒张试验阳性是指吸入400 μg沙丁胺醇后较基线的可逆性≥12%且增加200 mL。
总体而言，91%的病例确诊为哮喘，9%的受试者两项检查均为阴性。71%的受试者乙酰甲胆碱激发试验单独阳性，17%的受试者两项检查均阳性，而单独沙丁胺醇支气管舒张试验显著阳性的情况很少见（3%）。导致FEV下降20%的乙酰甲胆碱激发浓度（PC20M）与沙丁胺醇可逆性程度之间无相关性（P = 0.10）。基线FEV/用力肺活量比值与沙丁胺醇可逆性呈负相关（P < 0.001），但与PC20M无关（P = 0.1）。在人口统计学和免疫炎症特征方面，包括嗜酸性粒细胞性哮喘的比例，各组之间未发现差异。
我们得出结论，在不选择具有不同炎症特征的患者的情况下，乙酰甲胆碱激发试验在诊断哮喘方面优于沙丁胺醇可逆性试验。基线气道阻塞可预测可逆性程度，但不能预测高反应性。
