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

Abstract

PurposeThe 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.MethodsIn 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.ResultsA 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.ConclusionThe handheld expiratory flowmeter might be used as a screening device for COPD in Chinese primary care settings.