Figure 4. Associations between elevated MMP-9 prospective exacerbations.

Models were adjusted for age, race, sex, FEV₁ percent predicted, smoking status, chronic bronchitis, leukocyte count, and history of previous exacerbations. (A) Logistic regression was used to measure associations with ≥1 AECOPD, and (B) Poisson regression was used for exacerbation frequency. Boxes represent the point estimates (OR or IRR), and the horizontal bars represent the 95% CI. AECOPD, acute exacerbation of chronic obstructive pulmonary disease; MMP, matrix metalloprotease; OR, odds ratio; IRR, incidence rate ratio.