Fig. 3: The nomogram of COPD detection.

The nomogram illustrates the contribution of demographic information and the FEV1/FVC diagnostic gold standard to the model’s diagnostic accuracy for COPD. The nomogram allows for visual estimation of the probability of COPD diagnosis by assigning weighted scores to each variable. The “threshold” in the figure represents the cutoff value at which the predicted probability indicates a positive diagnosis for COPD. For instance, a threshold of 0.5 means that a predicted probability greater than 0.5 would be considered indicative of COPD.