Metabolic syndrome and ambulatory arterial stiffness index in non-diabetic patients with primary hypertension.

Increased arterial stiffness and the presence of metabolic syndrome (MS) have been shown to predict cardiovascular events in patients with primary hypertension. We investigated the relationship between a recently proposed index of arterial stiffness derived from ambulatory blood pressure (BP) monitoring and MS in 156 untreated, non-diabetic patients with primary hypertension. Ambulatory arterial stiffness index (AASI) was defined as 1 minus the regression slope of diastolic over systolic BP readings obtained from 24-h recordings. A modified National Cholesterol Education Program definition for MS was used, with body mass index replacing waist circumference. The prevalence of MS was 23%. Patients with MS were more frequently male (0.0291) and had increased serum uric acid (P=0.0005), high-sensitivity C-reactive protein (P=0.0259), as well as total and low-density lipoprotein (LDL)-cholesterol (P=0.0374 and P=0.0350, respectively) as compared to those without MS. After adjusting for these confounders, the association between AASI and the presence of MS was statistically significant (P=0.0257). Moreover, the prevalence of increased AASI (upper tertile, that is >or=0.550) was greater in patients with MS (P=0.0156). After adjusting for age and 24-h mean BP, the presence of MS entailed a more than twofold greater risk for increased AASI (0.0280). MS is associated with increased AASI in non-diabetic patients with primary hypertension. These data support the role of this new index of arterial stiffness as a marker of risk and help to explain the high cardiovascular morbidity and mortality that is observed in hypertensive patients with MS.