LAUSR

We’ve shown FOT staged COPD correlates better with patient reported outcomes (PROs) than spirometry (SP) staged COPD. We hypothesized non-obstructed subjects (non-OB, FEV 1 /FVC≥0.7) with either MMEF 130% predicted would be more similar to obstructed subjects (OB, FEV 1 /FVC X >9 cmH2O/L/s) by FOT. 300 COPD subjects (>10 pack-year smoking and either FEV 1 /FVC 130%predicted) had PROs (mMRC, COPD Assessment Tests, chronic bronchitis questionnaires and AERs), PFTs (Jaeger or Vmax22, Carefusion, Germany), FOT (tremoFlo C-100, Thorasys, Canada) and in a subset, quantitative CT scan lung density (LD) abstracted from charts. Subjects were assigned to 1 of 4 groups based on FEV 1 /FVC≥/ X >/≤9. Differences between continuous variables were determined with ANOVA and dichotomous with χ2. Significance was set at p While concordant phenotypes of non-VI/non-OB and VI/OB had a clear separation of disease burden in terms of PROs and emphysema, the discordant phenotypes of VI/non-OB and non-VI/OB resembled more their VI status than their OB status. Our data suggests that up to 19% of COPD subjects may be misclassified using SP.