Statistical analysis:
To compare metabolome profiles among groups, orthogonal partial least squares-discriminant analysis (OPLS-DA) was employed as a visualization tool. Emphasis was placed on identifying differential metabolites based on statistical significance, using Variable Importance in Projection (VIP) values from the OPLS-DA model and P values from the Mann Whitney U test on normalized peak areas. Specifically, metabolites with VIP values > 1 and P values < 0.05 were considered as differential metabolites. KEGG pathway enrichment analysis of these metabolites utilized the Fisher’s exact test and was compared with all identified metabolites. Correlation analysis employed Pearson’s correlation coefficient analysis, utilizing the corrplot R package.
Student’s t -test analyses were conducted to identify group differences. The potential predictive capability of factors for AMN-SARS-CoV-2 was evaluated using receiver operating characteristic (ROC) curves. The Spearman’s rank correlation test was employed to analyze correlations between variables. For all analyses, two-tailed probabilities were used, and significance was indicated by a two-tailed P value < 0.05.