Validity of the Handheld Expiratory Flowmeter for COPD Screening in the Primary Care Setting of China

Shuyun Chen,1,2,&ast; Xiaochen Li,1,3,&ast; Zihui Wang,1,&ast; Yumin Zhou,1 Dongxing Zhao,1 Zhuxiang Zhao,1,4 Sha Liu,1 Pixin Ran1 1State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, National Clinical Research Center for Respiratory Disease Guangzhou, First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, Guangdong Province, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People’s Republic of China; 3The People’s Hospital of Hubei Province, Wuhan, Hubei Province, People’s Republic of China; 4The First People’s Hospital of Guangzhou City, Guangzhou, Guangdong Province, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Pixin RanState Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Diseases, National Clinical Research Center for Respiratory Disease Guangzhou, First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, No. 195 Dongfeng Xi Road, Guangzhou, 510000, Guangdong Province, People’s Republic of ChinaTel +86 2083205187Email pxran@gzhmu.edu.cnPurpose: The use of simple and affordable screening tools for chronic obstructive pulmonary disease (COPD) is limited. We aimed to assess the validity of a handheld expiratory flowmeter (Vitalograph Ltd., COPD-6®, Ireland) for COPD screening in Chinese primary care settings.Methods: In our cross-sectional study, subjects were randomly selected in eight primary care settings. Tests with the handheld expiratory flowmeter and the conventional spirometry were sequentially performed on all participants. The correlation between the handheld expiratory flowmeter and the conventional spirometry was determined. Validity was determined by the area under the receiver operator characteristic curve (AUC) of the forced expiratory volume in one second (FEV1)/forced expiratory volume in six seconds (FEV6) that used to detect airway obstruction. The sensitivity, specificity, predictive values, and likelihood ratio were calculated according to different FEV1/FEV6 cut-off points.Results: A total of 229 subjects (15.4%) were diagnosed with airflow limitation by conventional spirometry. FEV1, FEV6, and FEV1/FEV6 measured by the handheld expiratory flowmeter were correlated with FEV1, FVC, and FEV1/FVC measured by the conventional spirometry (r=0.889, 0.835 and 0.647, p< 0.001), respectively. AUC of the FEV1/FEV6 to determine airflow obstruction was 0.857 (95% CI: 0.826 to 0.888). No significant difference of AUC was observed between the symptomatic group and the asymptomatic group (AUC=0.869 vs 0.843, P=0.425). A similar phenomenon was found in the AUC of smokers and never-smokers (AUC=0.862 vs 0.840; P=0.515). The cut-off point for FEV1/FEV6 was 0.77 and the corresponding sensitivity and specificity were 71.2% and 89.8%, respectively.Conclusion: The handheld expiratory flowmeter might be used as a screening device for COPD in Chinese primary care settings.Keywords: COPD screening, airflow limitation, FEV1, FEV6, lung function