Correlation between PD20 and FENO, EOS counts, EOS%, FEFs and R5-R20
FENO, FEF25%, FEF50%, FEF75%, and FEF25%-75% were weakly correlated with PD20 by Spearman analysis (Table 2). No significant correlation between PD20 and FEV3/FVC, EOS counts, EOS%, R5-R20, X5, or Fres was found. There was no difference in PD20 between subjects with chest tightness (0.065; IQR, 0.220) and those without this symptom (0.089; IQR, 0.349; P = 0.764).