Figure 2 Correlation of the selected biomarker panel with carbon monoxide transfer factor (Tlco) in patients with COPD. The size of the bar in the graph indicates the magnitude of the regression coefficients and the 95% confidence interval is also indicated for each bar. If the confidence interval includes zero, the associated biomarker is “not significant”. The overall regression model was significant by a permutation test (p<0.01). Definitions of the biomarkers are given in the footnote to table 4.