Figure 2.

The correlation between emphysema degree and sputum biomarkers (log IL-8 concentration [A, n=29] and log MPO activity [B, n=28]) and symptom score (CCQ [C, n=37] and MRC [D, n=37]) in COPD patients during stable phase (using the mean of each parameter at all stable visits).

Note: Data are presented as individual value for each patient, and Spearman’s r and P values are shown in the respective figure.

Abbreviations: CCQ, Clinical COPD Questionnaire; conc, concentration; IL, interleukin; MPO, myeloperoxidase; MRC, Medical Research Council.