Effect of metformin on blood pressure in obesity primary hypertension with impaired glucose tolerance

Objective To evaluate the efficacy of metformin on blood pressure in obesity primary hypertation patients with impaired glucose tolerance.Methods One hundred senile primary hypertation patients with impaired glucose tolerance who were not reached ideal blood pressure one month after ramipril(5 mg qd) treatment were randomized to metformin group(50 cases) and control group(50 cases).Both groups continued old lifestyle and medication.Metformin group used metformin(0.5 g tid) for 16 weeks.Before and after 16 weeks treatment 24 hours ambulatory blood pressure monitoring,height,weight,fasting and 2 hours postprandial plasma glucose,fasting and 2 hours postprandial plasma insulin were tested.Results Compared with those in control group and themselves before metformin treatment,there were significant decreases in 24 h mean systolic and diastolic blood pressure(P0.05),body mass index(BMI) and 2 hours postprandial plasma glucose(P0.05) and fasting and 2 hours postprandial plasma insulin(P0.05).The rate of efficiency on blood pressure in metformin group was 72%,it was higher than in control group(44%,P0.05).Meanwhile insulin sensitivity index(ISI) improved and insulin resistances index decreased significantly(P0.05),respectivetly.No one showed low plasma glucose reaction in metformin group.Conclusion Metformin showed good antihypertensive efficacy and safety in obesity primary hypertention patients with impaired glucose tolerance.