Figure 1From: Serum metalloproteinase-9 is related to COPD severity and symptoms - cross-sectional data from a population based cohort-study Association between FEV 1 % predicted and MMP-9 in COPD subjects, the lines show the linear association between MMP-9 and FEV 1 % predicted in each GOLD stage with the R 2 value indicating the strength of the association. Back to article page