Comparative effects of nebivolol and atenolol on blood pressure and insulin sensitivity in hypertensive subjects with type II diabetes

The aim of this double-blind, parallel group study was to compare the effects of nebivolol and atenolol on blood pressure (BP) and insulin sensitivity in hypertensive patients with type II, non-insulin dependent diabetes mellitus (NIDDM). After a 4-week run-in period on placebo, 30 patients (14 males and 16 females) aged 43 to 69 years, with stable NIDDM and mild to moderate hypertension (DBP > or =95 and <116 mm Hg) were randomised to receive either nebivolol 5 mg or atenolol 50 mg, both administered once daily for 6 months. At the end of the placebo and the active treatment periods, supine and standing BP was measured, 24-h urinary C-peptide, HbA1c, plasma glucose and lipid levels were evaluated and an euglycaemic hyperinsulinaemic clamp was performed to evaluate insulin sensitivity: glucose infusion rate during the last 60 min of clamp and total glucose requirements were evaluated. Nebivolol 5 mg once daily was of an equivalent efficacy as atenolol 50 mg once daily at reducing supine and standing systolic and diastolic BP values. Neither beta-blocker adversely affected carbohydrate metabolism in terms of insulin sensitivity, whole body glucose utilization, HbA1c and 24-h urinary C-peptide excretion. No significant changes in cholesterol (total, high density and low density lipoprotein) and triglycerides plasma levels were observed with both beta-blockers. These findings indicate that, in hypertensive patients with NIDDM, ie, in subjects who have established insulin resistance, treatment with nebivolol and atenolol neither further deteriorated insulin sensitivity nor adversely affected the lipid profile