Fig. 7: Quantitative analysis and model validation of secondary BAs in validation cohort.

a Dot histogram of the plasma levels of five secondary BAs in the patients with and without POAF from the validation cohort. Mann‒Whitney U test was used for each comparison. b Random Forest-based ROC curves using the five secondary BAs. The AUC value under the ROC curves and its 95% CI are shown. c Posterior classification probability plot based on 100 cross-validation. d The permutation test plot (1000 times).