Objectives: To investigate the value of exercise challenge testing (ECT) in the diagnosis of cough variant asthma (CVA) in children.
Methods: A prospective study was conducted on 78 children with chronic cough who were admitted between January 2023 and January 2024. ECT was performed, and clinical data were collected. According to the effect of bronchodilator treatment, the children were divided into a CVA group (44 children) and a non-CVA group (34 children), and the two groups were compared in terms of clinical characteristics, pulmonary function, and ECT results before treatment.
Results: Compared with the non-CVA group, the CVA group had a significantly higher proportion of boys, a significantly higher proportion of children with exercise-induced chronic cough, a significantly higher level of fractional exhaled nitric oxide, and a significantly greater reduction in forced expiratory volume in 1 second (FEV1) after ECT (P<0.05). The regression analysis showed that exercise-induced chronic cough and the reduction in FEV1 were risk factors for CVA (P<0.05). A reduction in FEV1 of 8.44% was the optimal cut-off value for ECT in the diagnosis of CVA, with an area under the curve of 0.751 (P<0.05), a sensitivity of 65.9%, and a specificity of 79.4%. For the children with exercise-induced chronic cough, a reduction in FEV1 of 8.44% was the optimal cut-off value for ECT in the diagnosis of CVA, with an area under the curve of 0.810 (P<0.05), a sensitivity of 77.1%, and a specificity of 77.8%.
Conclusions: ECT has clinical application value in the etiological diagnosis of pediatric chronic cough, with a reduction in FEV1 of 8.44% serving as the optimal cut-off value for diagnosing CVA. It is particularly suitable for children with exercise-induced chronic cough, increasing the sensitivity for CVA diagnosis.
目的: 探究运动激发试验（exercise challenge testing, ECT）对儿童咳嗽变异性哮喘（cough variant asthma, CVA）的诊断价值。方法: 前瞻性纳入2023年1月—2024年1月收治的78例慢性咳嗽患儿，进行ECT，收集临床资料。根据支气管舒张剂治疗效果分为CVA组（n=44）和非CVA组（n=34），分析比较两组治疗前临床特征、肺功能和ECT差异。结果: 与非CVA组相比，CVA组男童更多，运动诱发的比例更高，呼出气一氧化氮水平更高，ECT后第1秒用力呼气容积（forced expiratory volume in one second, FEV1）下降更显著（P<0.05）。二元logistic回归分析显示运动诱发因素和FEV1下降百分比高为慢性咳嗽患儿发生CVA的危险因素（P<0.05）。ECT诊断CVA的最佳切点值为FEV1下降超过8.44%，曲线下面积为0.751（P<0.05），灵敏度为65.9%，特异度为79.4%。在运动诱发性慢性咳嗽患儿中ECT诊断CVA的最佳切点值为FEV1下降超过8.44%，曲线下面积为0.810（P<0.05），灵敏度为77.1%，特异度77.8%。结论: ECT在儿童慢性咳嗽病因诊断中具有临床应用价值，以FEV1下降8.44%为诊断CVA的最佳切点值，尤其适用于运动诱发者，可提高灵敏度。.
Keywords: Child; Cough variant asthma; Exercise challenge testing.