Annangi Srinadh, Coz-Yataco Angel O
Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Kentucky College of Medicine, Lexington, Kentucky; and Division of Pulmonary and Critical Care Medicine, Harrison Memorial Hospital, Cynthiana, Kentucky.
Respir Care. 2022 Apr;67(4):440-447. doi: 10.4187/respcare.09215.
Bronchodilation testing is an important component of spirometry testing, and omitting this procedure has potential clinical implications toward diagnosing respiratory diseases. We aimed to estimate the impact of bronchodilator testing in accurately diagnosing COPD and differentiating COPD from asthma-COPD overlap (ACO).
The National Health and Nutrition Examination Survey data were analyzed from 2007-2012. Airflow limitation was defined by FEV/FVC < 0.7. Subjects with pre-bronchodilator airflow limitation were classified into pre-but-not-post-bronchodilator airflow limitation and post-bronchodilator airflow limitation groups. Spirometry-confirmed COPD was defined by persistent airflow limitation on post-bronchodilator spirometry. The American Thoracic Society (ATS) and the Spanish Society of Pneumology and Thoracic Surgery (SEPAR) definitions were used to identify possible ACO subjects.
We identified 11,763 subjects ≥ 40 y of age eligible for spirometry; 625 of them had a pre-bronchodilator FEV/FVC < 0.7 and completed post-bronchodilator spirometry that met ATS spirometry quality standards. A total of 244 (39%) of these subjects had only pre-not-post-bronchodilator airflow limitation, thereby not meeting the definition of spirometrically confirmed COPD. The prevalence of ACO was 7.6% using the modified ATS definition and 19.8% using the modified SEPAR criteria. When bronchodilator testing-based criteria were excluded from ATS and SEPAR definitions, the number of ACO subjects decreased by 39.3% and 12.3%, respectively.
Spirometry with bronchodilation is an important element in the accurate diagnosis of ACO and COPD. Spirometry performed without bronchodilator testing may lead to an estimated misclassification of ACO by 7.6% to 19.8% and overdiagnosis of COPD by 39%.
支气管扩张试验是肺量计测试的重要组成部分，省略该程序对呼吸系统疾病的诊断具有潜在的临床影响。我们旨在评估支气管扩张剂测试对准确诊断慢性阻塞性肺疾病（COPD）以及区分COPD与哮喘-COPD重叠综合征（ACO）的影响。
分析了2007年至2012年的美国国家健康与营养检查调查数据。气流受限定义为第一秒用力呼气容积（FEV）/用力肺活量（FVC）<0.7。支气管扩张剂使用前存在气流受限的受试者被分为支气管扩张剂使用前但使用后无气流受限组和支气管扩张剂使用后气流受限组。肺量计确诊的COPD定义为支气管扩张剂使用后肺量计检查显示持续气流受限。采用美国胸科学会（ATS）和西班牙肺科与胸外科协会（SEPAR）的定义来识别可能的ACO受试者。
我们确定了11763名年龄≥40岁且符合肺量计测试条件的受试者；其中625人支气管扩张剂使用前FEV/FVC<0.7，并完成了符合ATS肺量计质量标准的支气管扩张剂使用后肺量计检查。这些受试者中共有244人（39%）仅在支气管扩张剂使用前存在气流受限，因此不符合肺量计确诊的COPD定义。采用改良的ATS定义时ACO的患病率为7.6%，采用改良的SEPAR标准时为19.8%。当从ATS和SEPAR定义中排除基于支气管扩张剂测试的标准时，ACO受试者数量分别减少了39.3%和12.3%。
支气管扩张肺量计检查是准确诊断ACO和COPD的重要因素。未进行支气管扩张剂测试的肺量计检查可能导致ACO估计误诊率为7.6%至19.8%，COPD过度诊断率为39%。
