Fig. 2

ROC curve for the diagnosis of COPD using COPD-6™ at the GP’s office. ROC curve plot (AUC 0.827, 95 % CI 0.769–0.875, P < 0.001) was based on FEV1/FEV6 measurements using COPD-6™ at the GP’s office using COPD diagnosis made by pulmonologist at tertiary care hospital as criterion variable; dotted lines represent 95 % confidence intervals