Selection of predictor variables or characteristics
COPD
SEPARATION, DISEASE, COPD
In a first approximation, potential predictive characteristics were selected using the random forestFigure Process for preparation and selection of the characteristics of the evaluations.During the process of selecting characteristics, all those that were redundant or had very low variabilities were discarded. In this study, by definition, we did not have variables with perfect separation that could cause overestimation of the diagnostic capacity of the models (overfitting)In addition to the characteristics selected from the HR and Ox signals, the age, sex and baseline disease (HF or COPD) of the patients were considered potential predictors.