%0 Journal Article %A Matthew Hegewald %A Olinto Linares-Perdomo %A Dave Collingridge %A Robert Jensen %A John Hankinson %A Alan Morris %T Mortality and classification of airway obstruction severity by different methods %D 2016 %R 10.1183/13993003.congress-2016.PA1328 %J European Respiratory Journal %P PA1328 %V 48 %N suppl 60 %X BACKGROUND: Assessment of airflow obstruction severity is clinically important. The ATS/ERS Task Force recommended using FEV1% predicted for classification of obstruction severity. However, using FEV1% predicted does not adjust for lung size. Our objective was to adjust the FEV1% predicted for lung size and to use FEV1/FVC confidence intervals (CI) based strategy to determine if reclassifying obstruction severity affects mortality.METHODS: Adult patients tested in our PFT laboratory with airway obstruction based on a FEV1/FVC less than the lower limit of normal using NHANESIII reference equations and a TLC measurement were included. Classification of airway obstruction severity was determined using four methods: 1-FEV1% predicted (unadjusted); 2-FEV1% predicted adjusted by FVC% predicted; 3-FEV1% predicted adjusted by TLC% predicted; 4-FEV1/FVC CI strategy (Balfe, et al. Chest 2002; 22:1365-69).The association between the severity classifications for the four methods and all-cause mortality at five years was determined.RESULTS: Figure indicates that there are significant differences in the classification of obstruction severity and associated mortality. FEV1% predicted (unadjusted) is better correlated with mortality than the other classification strategies. CONCLUSION: Classifying obstruction severity by FEV1% predicted (recommended by ATS/ERS Task Force) is most correlated with all-cause mortality. %U