Trandolapril and verapamil reduce risk of developing diabetes in Hispanic patients

May 23 2006

The combination of drugs traditionally used to control blood pressure might not be ideal for Hispanic patients, University of Florida researchers warn.

While beta-blockers and diuretics have long been used to treat patients with hypertension, Hispanic patients appear to benefit from a tailor-made strategy that includes other medications, particularly calcium antagonists and angiotensin-converting, or ACE, inhibitors.

Not only does the approach effectively lower blood pressure in many Hispanic patients, it has an extra benefit: It dramatically cuts their risk of developing diabetes. UF researchers reported the findings in this month's issue of the American Heart Journal.

"We can successfully lower blood pressure in Hispanic patients with heart disease with medications that include beta-blockers like atenolol or calcium antagonists like verapamil plus the ACE inhibitor trandolapril, especially when compared with non-Hispanic patients," said Rhonda Cooper-DeHoff, Pharm.D., a research assistant professor and associate director of the clinical research program in cardiovascular medicine at UF's College of Medicine. "Lower blood pressure translated into fewer heart attacks and fewer strokes, which is very important for reducing cardiovascular risk in both Hispanics and non-Hispanics.

"The use of trandolapril and verapamil, however, also significantly reduced the risk of developing diabetes in Hispanic patients," she said.

Researchers involved in the landmark International Verapamil SR-Trandolapril study, known as INVEST, were intrigued by the finding in part because patients with high blood pressure and cardiovascular disease - in particular those of Hispanic descent, the fastest-growing ethnic minority in the United States - are much more likely to develop diabetes. Those who do are twice as likely to suffer serious complications associated with heart disease.

UF researchers tracked more than 22,500 patients from 14 countries - including about 8,000 Hispanics - for two to five years. The study enrolled more Hispanic patients than any other hypertension trial to date, Cooper-DeHoff said, and included Hispanic participants from the mainland United States, Puerto Rico, Cuba, Mexico, Canada, Guatemala, Panama and El Salvador.

Participants were randomly assigned to receive a sustained-release form of the calcium antagonist verapamil or the beta-blocker atenolol. Both groups also could receive the ACE inhibitor trandolapril and the diuretic hydrochlorothiazide.

Researchers found that both treatment strategies controlled high blood pressure exceptionally well, safely lowering it below 140/90 in 72 percent of INVEST participants, who were mostly elderly. On average, it took at least two medications to lower blood pressure in Hispanic patients, compared with three in non-Hispanic patients.

Overall, Hispanic patients had a 19 percent increased risk of developing diabetes during the study's follow-up period, but those in the verapamil group were actually 15 percent less likely to develop diabetes, and the addition of trandolapril to verapamil was linked to the decreased risk.

UF researchers said that one or two out of every 100 hypertensive heart disease patients treated with a verapamil SR-trandolapril strategy for at least three years could potentially avoid diabetes - an advance that would affect thousands.

Use of ACE inhibitors has been shown to improve the body's ability to use sugar for fuel, Cooper-DeHoff said.

"Because trandolapril was used more frequently in verapamil strategy, this is likely why we saw a reduced rate of new diabetes," she said, adding that preventing diabetes would have tremendous public health implications and could greatly cut related health-care costs.

UF researchers also will continue to analyze DNA they have collected from Hispanic study participants to evaluate the role of genes and environmental factors such as diet on diabetes development.

Cooper-DeHoff collaborated on the study with UF cardiologists Carl J. Pepine, M.D.; C. Richard Conti, M.D.; and Juan M. Aranda Jr. M.D., along with researchers from Mexico, Puerto Rico and Cuba. The study was funded by grants from UF and Abbott Laboratories, for which Pepine served as a consultant. Cooper-DeHoff was on the company's speaker's bureau.

Regardless of race or ethnicity, lowering blood pressure is extremely important in reducing future cardiovascular risk, Cooper-DeHoff said.

"Even lowering blood pressure two or three millimeters of mercury is associated with significant reduction in the risk of subsequent stroke," she said. "It's very important even for those with mild hypertension to seek treatment. And if we can choose medications in Hispanic patients that reduce the risk of developing diabetes, that's an important thing for physicians prescribing blood pressure-lowering medications to keep in mind."