Blood-Pressure Drugs May Increase Diabetes Risk

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March 29, 2000 (Lake Tahoe, Calif.) -- People who take a type of drug called beta-blockers to control their high blood pressure may want to discuss its use with their physician if they are overweight or have a family history of diabetes.

A study in the March 30 issue of The New England Journal of Medicine found that people taking beta-blockers had a 28% higher risk of developing diabetes. The researchers also confirmed that people with high blood pressure have 2.5 times the risk of developing diabetes as those with normal blood pressure.

"Lots of people are taking beta-blockers for other reasons [than high blood pressure], and there's strong evidence that they are beneficial to some patients with heart disease. However, [for] a patient with the potential to develop diabetes and [who] has no other reason to take beta-blockers, there may be other choices," study co-author Marion R. Wofford, MD, MPH, tells WebMD.

Diuretics, another class of antihypertension drug, were not associated with a higher risk of diabetes, Wofford says. Wofford is assistant professor of medicine in the division of hypertension at the University of Mississippi Medical Center in Jackson.

From 1987 to 1989, more than 12,000 adults aged 45-64 were tested and assigned into two groups depending on whether they had high blood pressure. Antihypertension medications used by the almost 4,000 participants with high blood pressure were broadly classified into one of five categories: ACE inhibitors, beta-blockers, calcium channel antagonists, thiazide diuretics, or other single agents. Nearly 1,500 subjects were not taking any medication.

Three years after enrolling in the study and again six years later, the subjects were tested for diabetes (with a fasting blood glucose test) and were questioned about their use of insulin or oral hypoglycemic drugs and/or a physician's diagnosis of diabetes mellitus.

After eliminating the effects of age, sex, race, and the use of other medications, the investigators found that "subjects who were taking a thiazide diuretic, ACE inhibitor, or calcium-channel antagonist were not at greater risk for the subsequent development of diabetes mellitus than were their untreated counterparts. In contrast, diabetes mellitus was 28% more likely to develop in subjects taking a beta-blocker than those taking no medication."

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"This is an important study that adds to the body of knowledge, and I think the results are probably valid," Richey Sharrett tells WebMD. Sharrett, a senior scientific advisor in the epidemiology and biometry program at the National Heart, Lung, and Blood Institute in Bethesda, Md., was not involved in the study.

Sharrett said he is concerned that reports of this study might alarm people who are taking beta-blockers. "Beta-blockers are very effective in preventing coronary artery disease," he says. He encourages people with a family history of diabetes to discuss with their physician the benefits and risks of taking this class of drugs, and to become informed about the symptoms of diabetes.

"There should be no immediate stopping of beta-blockers, because even though there is an increased likelihood [of diabetes], it certainly isn't 100%," says Norman M. Kaplan, MD, who is spokesman for the American Heart Association. Kaplan, who is also a professor of medicine at the University of Texas Southwestern Medical School in Dallas, reviewed the study for WebMD.

Kaplan says there are specific indications for beta-blockers, including chest pain or angina, certain types of rapid heartbeat, and heart attack. He recommends that people who are obese and/or have a family history of diabetes ask their physician if there is a good reason for them to take a beta-blocker.

If there is no particular reason, he says, "then another type of drug might be a better alternative."

Vital Information:

  • Patients with high blood pressure who take beta-blockers appear to have a 28% increased risk of developing diabetes.
  • This association was not seen with any other class of blood-pressure medication.
  • Patients who are taking beta-blockers and are overweight or have a family history of diabetes should ask their doctors whether other medicines are just as effective.
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