Glucose tolerance & insulin response in patients with hypertension.

ABSTRACT

Background: Insulin resistance leads to impaired glucose tolerance, dyslipidemia, and other adverse cardiovascular effects. Euglycemic insulin clamp have shown that essential hypertension per se is a state of insulin resistance and has been associated with an increased incidence of diabetes Aims: To ascertain the prevalence of several degrees of glucose abnormalities in patients with hypertension and to examine the insulin secretory response to oral glucose load. Study design, Material and Method: This cross-sectional analytical study included 325 hypertensive patients (with or without diabetes)and 100 control subjects. An oral glucose tolerance test (OGTT) following WHO guidelines was performed in all subjects, with measurement of insulin at baseline and every 30 minutes after the glucose load. Results: Abnormal glucose metabolism was observed in 70.77% of patients (95% confidence interval [CI], 65.87% - 74.21%). Of the 325 patients, 29.23% patients showed normal glucose metabolism. Impaired glucose tolerance (IGT) and Impaired fasting glycemia (IFG) were diagnosed in 30.46% and 16.61% patients respectively .Total diabetic population in the hypertensive patients were 23.69% (silent previously undiagnosed diabetes mellitus was diagnosed in 9.53% of patients while 14.15%reported a previous diagnosis of diabetes mellitus).Decreasing glucose tolerance was associated with insulin resistance. From normal glucose tolerance condition through IGT, IFG to diabetic, the HOMA IR progressively increased. Results of standard OGTT and corresponding insulin response after 0, 30, 60 and 120 minutes were significantly higher in patients compared with control subjects. LVMI and severity of glucose intolerance were significantly related. Male gender, higher levels of insulin (fasting insulin/HOMA IR) and greater adiposity (BMI) were all strongly associated with the severity of glucose abnormalities. Prevalence of metabolic syndrome increased progressively with severity of glucose abnormality. Conclusions: More than two-third of the hypertensive patients exhibited different glucose abnormalities and exaggerated insulin response to glucose load (hyperinsulinemia) along with cluster of other cardiovascular risk factors, whose prevalence increases with severity of glucose intolerance.