New beta blocker may help diabetic patients with high blood pressure

A medication that is commonly used to control high blood pressure does not raise blood sugar levels in diabetics who also have high blood pressure, according to researchers from Rush University Medical Center.

The results of the study appear in the November 10 issue of the Journal of the American Medical Association (JAMA) and were presented today at the 2004 American Heart Association Scientific Sessions.

Beta blockers have been shown to be effective at lowering high blood pressure but many physicians have been reluctant to prescribe them to patients with diabetes because some beta-blockers have been shown to raise blood sugar levels in diabetics.

Especially at risk are the estimated 47 million people with metabolic syndrome, a combination of several risk factors in one person that includes, but is not limited to, high blood pressure, insulin dependence or glucose intolerance, and obesity.

"The results of this study suggest that physicians treating diabetic patients may want to consider the role that a newer beta-blocker such as carvedilol could play in managing certain cardiovascular risk factors and components of the metabolic syndrome," said Dr. George L. Bakris, director, hypertension research center at Rush University Medical Center. "By improving these crucial risk factors, carvedilol could, theoretically, improve overall outcomes in this high-risk patient population."

Bakris was the principal investigator of this 1,235-patient study, which is known as GEMINI (Glycemic Effects in Diabetes Mellitus: Carvedilol - Metoprolol Comparison in Hypertensives). Bakris and colleagues compared the effects of carvedilol to metoprolol tartrate in diabetic, hypertensive patients. Patients were randomized to receive carvedilol or metoprolol tartrate each twice daily, and were followed for a minimum of 5 months.

Patients in the carvedilol arm reached blood pressure goals at a mean daily dose of 18 mg twice daily, which closely matches the dose that is commonly prescribed in clinical settings. Patients receiving metoprolol tartrate required a mean daily dose of 128 mg twice daily to receive a similar benefit. In terms of diabetes control, carvedilol demonstrated no effect on blood sugar maintenance (as measured by Hba1c), while metoprolol tartrate significantly increased it despite patients taking antidiabetic therapies. Insulin resistance was reduced significantly in the carvedilol arm by 9.1 percent, while metoprolol tartrate had no effect on insulin resistance.

Carvedilol was also associated with a 40 percent reduction in the risk of developing microalbuminuria, an important marker of cardiovascular disease risk, as compared to metoprolol tartrate. Finally, patients taking carvedilol did not gain weight, while patients taking metoprolol tartrate had significant weight gain of 2.6 pounds.

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