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 >= 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.