Fig. 5

Construction of a nomogram model. A A nomogram was constructed to predict poor exercise tolerance (6MWD < 350 m) in COPD patients. B Calibration curves for the nomogram for the prediction of poor exercise tolerance (6MWD < 350 m) in COPD patients. C ROC curve analysis showing that the highest AUC value corresponded to the nomogram model. D Decision curve analysis showing the net benefit of the nomogram model for the prediction of poor exercise tolerance (6MWD < 350 m)