Induction of insulin resistance by beta blockade but not ACE-inhibition: longterm treatment with atenolol or trandolapril

The effects on glucose metabolism by the beta-blocker atenolol and the angi otensin-converting enzyme (ACE)-inhibitor trandolapril were investigated in a randomised double-blind parallel group study of patients with primary hy pertension. Twenty-six patients were treated with 50-100 mg atenolol and 27 patients with 2-4 mg trandolapril o.d. Intravenous glucose tolerance tests , euglycaemic hyperinsulinaemic clamps and serum lipid measurements were pe rformed after 8 and 48 weeks of active treatment. After 48 weeks insulin se nsitivity was reduced by 23% by atenolol while it remained unchanged during trandolapril treatment (+0.5%, P = 0.0010 for difference between treatment s, ANCOVA). The effect on triglycerides (+22% vs -8.5%) and high-density li poprotein cholesterol (-13% vs +0.7%) also differed significantly between a tenolol and trandolapril. Results after 8 weeks were similar. Glucose toler ance was not affected by either drug. Atenolol reduced diastolic blood pres sure (DBP) better than trandolapril (-15.3 mm Hg vs -6.6 mm Hg for supine D BP after 48 weeks, P = 0.072). The difference in effect on insulin sensitiv ity between the drugs corresponded to 25% of the baseline values of insulin sensitivity, and persisted over 48 weeks of treatment. The choice of antih ypertensive treatment could influence the risk of diabetes associated with treated hypertension.