Impacts of Different Spirometry Reference Equations and Diagnostic Criteria on the Frequency of Airway Obstruction in Adult People of North China

Mengshuang Xie, Liwei Cui, Jinhuan Liu, Wei Wang, Jun Li, Wei Xiao Department of Pulmonary and Critical Care Medicine, Qilu Hospital, Shandong University, Jinan, People’s Republic of ChinaCorrespondence: Wei XiaoDepartment of Pulmonary and Critical Care Medicine, Qilu Hospital, Shandong University, 107 Wenhua West Road, Jinan 250012, People’s Republic of ChinaTel/ Fax +86 53182166294Email xiaowei4226@163.comBackground and Objective: The reference equations and diagnostic criteria play a critical role in the interpretation of pulmonary function tests (PFTs). The aim was to investigate the impacts of different reference equations and diagnostic criteria on the frequency of airway obstruction in adult people of a large teaching hospital of North China.Methods: The spirometry data of all adult people who underwent PFTs in Qilu hospital from April 2012 to November 2015 were collected. Two spirometry reference equations, namely, Zhongshan-2011 and Global Lung Function Initiative 2012 (GLI-2012) were compared. The frequency of airway obstruction using different spirometry prediction equations and diagnostic criteria including forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 92% of predicted value and FEV1/FVC