NPPB and metabolic syndrome: Compared with the conventional model with incorporating traditional risk factors such as age, BMI, BNP, hypertension, diabetes and dyslipidemia (Harrell’s C-index: 0.741; 95%CI: 0.644–0.838), incorporation of global FD (Harrell’s C-index: 0.767; 95%CI: 0.673–0.860), maximal basal FD (Harrell’s C-index: 0.753; 95%CI: 0.659–0.848), and mean basal FD (Harrell’s C-index: 0.806; 95%CI: 0.722–0.891) into the prediction model improved the Harrell’s C-index, while the simultaneous inclusion of the three FD (Harrell’s C-index: 0.824; 95%CI: 0.744-0.95) led to the highest Harrell’s C-index (Table 4).