Fig. 2

Mean biomarker concentrations per sub-group. One-way ANOVA test of differences between COPD phenotypes and controls were made using Tukey’s multiple comparisons test. The Mixed disease group (“Chronic Bronchitis/Emphysema”, n=15) was defined as emphysema as diagnosed using CT and chronic bronchitis. The Emphysema group was defined as diagnosed emphysema using CT in the absence of chronic bronchitis (n = 30). The obstruction group was defined as the absence of both emphysema and chronic bronchitis, yet with the presence of significant respiratory obstruction diagnosed using spirometry (n = 7). C1M: Type I collagen degraded by matrix metalloproteinases. C6M: Type VI collagen degraded by matrix metalloproteinases. Pro-C6: Pro-peptide fragment of type VI collagen. EL-NE: Elastin degraded by neutrophil elastase