Plasma metabolomics reveals progressive alterations across glycemic states

Figure 4 Least absolute shrinkage and selection operator-based selection of candidate discriminative metabolic biomarkers, discrimination performance, and clinical associations. A: Least absolute shrinkage and selection operator coefficient profiles of candidate metabolites for discriminating between the normal glucose tolerance (NGT) and impaired fasting glucose (IFG) groups; B: Cross-validation curve of the least absolute shrinkage and selection operator model. The dashed lines indicate the lambda values corresponding to the minimum error criterion (lambda.min) and the 1-SE criterion (lambda.1se), respectively. Based on model parsimony and robustness, lambda.1se was selected to identify the final metabolite panel; C: Receiver operating characteristic curve of the final metabolite panel for discriminating between the NGT and IFG groups, with the optimism-corrected area under the curve shown; D: Receiver operating characteristic curves evaluating the stage-wise discriminative performance of the selected metabolite panel for the comparisons of NGT vs IFG, impaired glucose tolerance, and diabetes; E: Boxplots showing the distribution of the selected metabolites across the NGT, IFG, impaired glucose tolerance, and diabetes groups. ^bP < 0.01; F: Spearman correlation heatmap showing the associations between the selected metabolites and clinical indicators; color intensity represents Spearman correlation coefficients. AUC: Area under the curve; HbA1c: Glycated hemoglobin; FPG: Fasting plasma glucose; 2-h PG: 2-hour plasma glucose; HOMA-IR: Homeostasis model assessment of insulin resistance; TG: Triglycerides; HDL-C: High-density lipoprotein cholesterol; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; BUN: Blood urea nitrogen; Cr: Creatinine; BMI: Body mass index. A: Normal glucose tolerance; B: Isolated impaired fasting glucose; C: Isolated impaired glucose tolerance; D: Diabetes.