CRP and respiratory failure: The ROC curve analyses confirmed that there were significant differences for the AUC, when suPAR was added to age, sex, Charlson score and CRP in the two COPD groups but not for Respiratory failure (not shown).Calculations of the sensitivity and specificity of log-transformed suPAR yielded values of 0.78 and 0.49, respectively, for 30- days mortality in the largest patient group (Additional file 1: Table S1).