The American ALLHAT trial showed diuretics were superior to ACE (angiotensin-converting enzyme) inhibitors and calcium channel blockers in controlling blood pressure.

"However, we have showed that the ACE inhibitor is a little better; 11 percent," says study author Dr. Christopher M. Reid of the Baker Heart Institute in Melbourne. The report appears in the Feb. 13 issue of The New England Journal of Medicine.

It was not so much the results of the American trial but the way they were announced -- at a press conference in December with great fanfare -- that caused controversy in the cardiology community. However, there were also complaints that the ALLHAT report did not include a logical endpoint of treatment -- death from cardiovascular disease.

"I was absolutely passionate about it," says Dr. Michael A. Weber, a professor of medicine at the State University of New York Downstate College of Medicine and past president of the American Heart Association.

The differing results could have been due to the difference in the ethnic makeup of the two trials, Reid says. "Thirty percent of the ALLHAT subjects were black Americans, who are known not to respond to ACE inhibitors," he explains.

Almost all the 6,083 people in the Australian trial were white. Blood pressure reduction was the same in those who took a diuretic and those who took an ACE inhibitor. The incidence of stroke was the same in both groups, but the number of deaths from cardiovascular disease was 11 percent lower in the ACE inhibitor group.

For most patients, the conflicting results of the two trials will not make much difference, the cardiologists agree. There is general agreement that almost all people with high blood pressure need to take to more than one drug, Reid and Weber say.

"From our study, if you were over 65, we should recommend starting with an ACE inhibitor and then using a diuretic," Reid says. "From ALLHAT, you would recommend starting with a diuretic and then adding a calcium channel blocker or an ACE inhibitor. Irrespective of the studies, the choice of agent that best suits the patient and the agent with which they are most compliant and comfortable would be the agent of choice."

Other individual factors can affect the choice, says Dr. Edward D. Frohlich, who holds the title of distinguished scientist at the Ochsner Clinic Foundation. He has just stepped down as editor of the journal Hypertension and wrote an accompanying editorial.

"All other things being equal, I would prescribe a diuretic," Frohlich says. "If the patient has diabetes, I would use an ACE inhibitor. If he or she has angina, I would use a calcium channel blocker."

The two studies have one thing in common, Weber says: "Both emphasize how important it is to get blood pressure under control."

Guidelines for treatment "are being rewritten at the moment," Reid says. "I think we will get to the situation where there will be specific recommendations for groups [elderly, diabetic, ethnic]. However, I don't think the message will be very different. The key factor will be the gent which best suits that individual."

More information

Learn about the medications used to control blood pressure from the American Heart Association. Meanwhile, read about the ALLHAT trial at the National Heart, Lung, and Blood Institute.