Hyperinsulinemic response to oral glucose in obese patients with essential hypertension

Background and objectives: Hypertension is a common health problem. The prevalence of hypertension increases progressively with increasing Body Mass Index. The aim of this study is to investigate changes in blood pressure (BP), plasma glucose (PG) and insulin level after ingestion of oral glucose; and to assess the relation between insulin level and BP in obese and non-obese normo-tensive and hypertensive subjects. Materials and Methods: Seventy five g glucose dissolved in 250 ml of water was given orally to 20 fasting newly diagnosed untreated patients with essential hypertension and 15 normo-tenisve control subjects matched for age, gender and Body Mass Index (BMI). Smokers and subjects with diabetes, hyperlipidemia, cardiac or renal disease or those taking medications were excluded. Subjects were monitored for 2 hours.Half hourly BP, PG and insulin were measured. Results: Subjects were classified into obese (BMI≥ 30 Kg/m2) (11 patients, 8 normo-tensives) and nonobese (BMI< 30 Kg/m2) (9 patients, 7 normo-tensives). In obese hypertensive patients, insulin showed significant positive correlation with: systolic BP (SBP) (P=.04), diastolic BP (DBP) (P=.04) and mean BP(MBP)(P=.03). Obese hypertensive patients showed a significantly higher insulin response to oral glucose than obese normo-tensive subjects (P=.02).In obese and non-obese hypertensive patients glucose intake was associated with significant drop in DBP((P≤ .005), (P< .05)) and MBP ((P< .005), (P< .05)) respectively.Conclusions: In obese hypertensive patients, the hyperinsulinemic response to oral glucose and the positive correlation of insulin with BP suggest that insulin may be involved in development of essential hypertension especially in obese patients