9.16 Hypertension Leads to Type 2 Diabetes Mellitus

Introduction. In this study we analyzed the influence of high blood pressure on development of type 2 diabetes mellitus. The association between high blood pressure and type 2 diabetes mellitus, documented by a numbers of epidemiologic studies, implies a common pathophysiologic mechanism. Hyperinsulinaemia seems to represent a pertinent hypothesis.

Methods. We studied patients with normal glucose tolerance by OGTT, according to ADA 2003, and with normal BMI (<25 for the men, <23.9 for the women). These criteria which exclude conditions in which insulin plays a prominent role allowed the recruitment of 207 patients (83 men and 124 women, aged 46.1 ± 14.7 years), subdivided into two different groups: group A included 97 patients with high and, group B 110 with normal blood pressure.

Results. Comparison between groups were performed on OGTT data derived (fasting and 2nd hr glucose and insulin blood levels), the HOMA-IR insulin-resistance index, (fasting glycaemia x fasting insulin/22.5), the lipid profile with apoprotein A and B, fibrinogen and microalbuminuria. BMI and the waist circumference, though remaining within normal were elevated in high blood pressure patients. The statistical analysis (MANOVA) disclosed, independent from age, BMI and waist circumference, group A presented in comparison with group B: statistically higher fasting blood insulin (A: 7.64 ± 3.64 vs B: 6.55 ± 2.99 microIU/ml, p < 0.01). Statistically higher HOMA IR (A: 1.6 ±s 0.73 vs 1.3 ± 0.65, p <0.01). Statistically higher fibrinogen (A: 293 ±s 60.4 vs B 309 ±s 53. 5 mg/dl, p<0.05) and microalbuminuria (A: 23 ± 36.4 vs B:12 ± 14.4 mg/24h) (P < 0.02 for both).

Conclusions. Our data indicate that, within normal glucose tolerance and anthropometric parameters, patients with high blood pressure have higher insulin resistance than patients with normal blood pressure, even though fasting and 2nd hour blood glucose are no different between groups. Insulin resistance could represent the initial step in the development of diabetes, accounting that high blood pressure it self constitutes a risk factor for the development of diabetes. Introducing the routine execution of OGTT implemented by insulin measurement could be of major help in preventing and/or delaying the onset of type 2 diabetes.