NPPB and metabolic syndrome: In contrast to subjects with CaA level ≥8.87 mg/dl, there was a significantly increased risk of declined HRV in subjects with CaA level <8.87 mg/dl [OR (95% CI), 0.049 (0.024–0.099), p < 0.001] after adjusting for possible confounding factors including creatinine, serum phosphate, age, gender, smoking, drinking, HbA1c, Ln(NT-proBNP), hs-CRP, TyG index, dyslipidemia, hypertension, coronary heart disease, carotid atherosclerosis, and the use of hypertension medication.