Close relationship of abnormal glucose tolerance with endothelial dysfunction in hypertension

Hypertension is frequently accompanied by left ventricular hypertrophy, end othelial dysfunction, and abnormal glucose metabolism. However, no study ha s examined the relative pathological significance of left ventricular hyper trophy and abnormal glucose metabolism on endothelial dysfunction in hypert ension. This study was conducted to evaluate whether abnormal glucose toler ance assessed by 75-g oral glucose tolerance test or left ventricular hyper trophy is more closely associated with endothelial dysfunction in never-tre ated hypertensive patients without elevated fasting blood glucose. We studi ed 107 unmedicated hypertensive patients (mean age, 54+/-10 years) whose fa sting blood glucose was <7.0 mmol/L. Endothelial function was assessed by c hange in brachial artery diameter in response to reactive hyperemia, and le ft ventricular mass index was determined by ultrasonography. Simple linear regression analysis demonstrated that endothelial function significantly co rrelated with left ventricular mass index and 2-hour blood glucose in 75-g oral glucose tolerance test, but not with fasting blood glucose. Multiple l inear regression analysis revealed that endothelial function significantly correlated with 2-hour blood glucose (beta = -2.68, P<0.05) after we contro lled for other clinical variables. Patients were divided into 3 groups acco rding to 2-hour blood glucose levels. Endothelial function was more impaire d in patients with diabetes (n=12; 4.7+/-1.8%) and in those with impaired g lucose tolerance (n=31; 6.3+/-2.9%) than in those with normal glucose toler ance (n=64; 8.4+/-4.5%) (P<0.05), but left ventricular mass index was simil ar in these 3 groups. Abnormal glucose tolerance assessed by 75-g oral gluc ose tolerance test, rather than left ventricular hypertrophy, may have dire ct pathophysiological relevance to endothelial dysfunction in borderline to moderate hypertensive patients.