Figure 5. Comparative analysis of the plasma metabolome could differentiate the severe and nonsevere COVID-19 patient groups.

(A) Volcano plot of the nonsevere and severe groups; purple dots are significant in fold change and adjusted p-value. (B) The expression level change (Z-scored original value) of eight selected metabolites with significant adjusted p-values and fold change; green boxes are the severe sample, and red boxes are the nonsevere sample. Asterisks indicate statistical significance based on unpaired two-sided Welch's t-test. (C) Heat map of selected average plasma metabolite expression levels. (D) Severe and nonsevere groups were separated with component one and two in partial least squares discriminant analysis machine-learning analysis. (E) Receiver operating characteristic with ten metabolites. (F) Fifteen metabolites prioritized by random forest analysis ranked by the mean decrease in accuracy.

*p < 0.05; **p < 0.01; ***p < 0.001.