Predictors for prehypertension in patients with impaired glucose tolerance.

Prehypertension (PHT) is associated with increased risk of cardiovascular disease and progression to hypertension. Insulin resistance and hyperinsulinemia have been reported among patients with hypertension. In addition, impaired glucose tolerance (IGT) is a strong predictor of not only of type 2 diabetes but also of cardiovascular disease. However, little is known about the impact of insulin resistance on recently defined categories of hypertension and IGT. The aim of this study was to examine associations of surrogate makers of insulin resistance with PHT and IGT. In a total of 102 IGT patients with normotension and PHT (age: 58+/-5 years; mean+/-SD), blood pressure measurement, 75 g oral glucose tolerance testing (OGTT), metabolic analysis and echocardiography were performed. Body mass index was higher in the PHT group than in the normotension group (p<0.05). The fasting immnunoreactive insulin (F-IRI) (p<0.0001), homeostasis model assessment (HOMA) index (p<0.0001), 30 min postload glucose (p<0.05), 60 min postload glucose (p<0.05), 120 min postload glucose (p<0.01), 120 min postload insulin (p<0.0001) and left ventricular mass index (LVMI) (p<0.0005) were higher in the PHT group than in the normotension group. Multivariate logistic analysis revealed that the presence of PHT was independently predicted by F-IRI. Our findings indicate that the presence of PHT was associated with hyperinsulinemia and that the F-IRI was an independent predictor of PHT in these Japanese patients with IGT.