Figure 7. Receiver Operating Characteristic (ROC) curves analysis for the predictive model with a combination of metabolites calculated from the logistic regression analysis using different metabolites selected by the VIP (> 1.0) values respectively for a) COVID-CTRL and c) COVID-RECOV. Predictive accuracy plot of biomarker models with an increasing number of features to discriminate between b) COVID and CTRL and d) COVID and RECOV. The most accurate biomarker model is highlighted by the red dots. Predicted class probabilities based on a structure of a 2 × 2 matrix to assess the performance of a classification model: e) COVID-CTRL groups; and f) COVID-RECOVERED groups.
The boxplots of the most important variables (VOMS) for discriminating between COVID and CTRL groups, and between COVID and RECOV, were plotted (Figure 8).