Figure 4.

(A) FEV₁ % predicted, (B) FEF_25%-75%, and (C) SGRQ total score among subjects with COPD by luminal plug status at phase 1. The box plots show the median (horizontal line in the middle of the box), mean (diamond), and 25th and 75th percentiles (bottom and top lines of the box) of FEV₁ % predicted, FEF_25%-75%, and SGRQ total score. The whiskers represent the upper and lower values (1.5 times above the 75th percentile and below the 25th percentile, respectively). P < .0001 for the difference in FEV₁ % predicted, FEF_25%-75%, and SGRQ between those with and without luminal plugging in univariate analysis. See text for details in adjusted models for these outcomes. FEF_25%-75% = forced expiratory flow at 25% to 75% of the FVC; SGRQ = St. George’s Respiratory Questionnaire.