Background: There is evidence that diuretics and beta blockers impair glucose tolerance, whereas calcium channel blockers and angiotensin converting enzyme blockers lack this metabolic effect. We compared the effect of a combination therapy with a nondihydropyridine calcium channel blocker plus an angiotensin converting enzyme inhibitor and a beta blocker plus a diuretic on hemoglobin A(1c) (Hb A(1c)) in patients with type 2 diabetes and mild-to- moderate hypertension.
Methods: A total of 463 hypertensive outpatients with non-insulin treated type 2 diabetes on stable antidiabetic therapy for at least 3 months and with HbA(1c) between 6.5% and 10% were recruited. In a randomized, double blind trial patients were treated for 20 weeks with fixed combinations of verapamil sustained release (SR) plus trandolapril and of atenolol plus chlorthalidone following a 2-week placebo run-in period. The main outcome measures were HbA(1c), fasting plasma glucose, and fructosamine levels as well as systolic and diastolic blood pressure.
Results: HbA(1c) remained stable at 7.9% after administration of verapamil SR plus trandolapril and increased from 7.8% to 8.6% with atenolol plus chlorthalidone; the differences between treatment groups were significant at 4, 12, and 20 weeks of treatment and at last visit (P <.0001). Mean blood pressure fell from 169/96 to 150/85 and from 168/95 to 145/83 mm Hg after administration of verapamil SR plus trandolapril and atenolol plus chlorthalidone, respectively. Both combinations were well tolerated.
Conclusions: HbA(1c) and other parameters of short- and long-term glycemic control were in a more favorable range after antihypertensive treatment with verapamil SR plus trandolapril as compared with atenolol plus chlorthalidone.