Diuretics most effective hypertension drug

Results from a five-year trial support this class of drugs as a first-line medication for high blood pressure treatment.

By Susan J. Landers, AMNews staff. Jan. 20, 2003. Additional information

Washington -- Heads up! Patients may soon be asking if they should switch their high blood pressure medications to an older, and much cheaper, class of drugs -- diuretics.

Findings from a federal study, published in the Dec. 18, 2002 JAMA, have determined that the medication first introduced in the 1950s is often more effective than newer and more costly drugs at lowering high blood pressure. Those findings are generating a great deal of attention.

The trial was the largest to test diuretics against the newer calcium channel blockers and ACE inhibitors. Beta-blockers were not included. An arm of the trial to test alpha-adrenergic blockers was stopped in March 2000 because of increased cardiovascular problems for those subjects.

While all three classes of drugs tested during the nearly five-year-long trial lowered blood pressure and reduced cardiovascular complications, diuretics were more likely to prevent heart failure and strokes, especially among African-Americans. There was no difference in overall deaths among participants.

Many of the participants were prescribed a second drug to control their blood pressure.

The specific drugs tested in the trial were the diuretic chlorthalidone, the calcium channel blocker amlodipine and the ACE inhibitor lisinopril.

50 million Americans have high blood pressure.

The implications of the findings are enormous. Some 50 million Americans have high blood pressure, increasing their risks for heart attack, heart failure and stroke.

This large potential use for antihypertensive drugs prompted a flood of such medications onto the market over the years. As a result, physicians are able to choose from among more than 100 approved medications representing seven major drug classes.

But the question has always been: Which drugs work best?

The study investigators believe the trial, called ALLHAT for Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, answers that question.

"The take-home message is that doctors should begin drug treatment for high blood pressure with a diuretic," said epidemiologist Paul Whelton, MD, senior vice president for health sciences at Tulane University Health Sciences Center in New Orleans and an ALLHAT regional coordinator.

"For patients whose high blood pressure is already being treated with medication other than a diuretic, physicians should consider switching to a thiazide-type diuretic or adding diuretics to the existing regimen," said Dr. Whelton, during a December 2002 media briefing on the trial's findings.

High blood pressure is a major risk factor for heart attack, heart failure and stroke.

Dr. Whelton acknowledged that physicians still need to take into consideration other conditions that patients may have that could influence drug choice, such as angina pectoris.

The cost of treating hypertension would drop dramatically if there is a major shift to diuretics as a first-line treatment or as part of a regimen.

For example, according to the JAMA article, previous data demonstrated that diuretic use declined from 56% to 27% of antihypertensive prescriptions between 1982 and 1992. However, the health care system would have saved $3.1 billion in estimated cost of antihypertensive drugs had the pattern of prescriptions for treatment of hypertension remained at the 1982 level.

Diuretics would also be much more affordable for patients who lack health insurance or coverage for medications. The drugs cost six cents to 10 cents per day compared with a cost of about $1 per day for ACE inhibitors.

To help spread the word to doctors that diuretics should be seriously considered as a treatment for high blood pressure, a committee was appointed to develop new clinical guidelines.

"We are deeply committed to applying these research findings in order to improve the health of the nation," said Claude Lenfant, MD, director of the Heart, Lung, and Blood Institute, which sponsored the trial.

The 700 investigators involved in the trial will also help disseminate the findings, and medical organizations will be asked to pitch in, said Curt Furberg, MD, chair of the ALLHAT steering committee and a professor of public health sciences at Wake Forest University Baptist Medical Center in Winston-Salem, N.C. "We will go full press," he said.

The trial also included a cholesterol-lowering study that supported current recommendations that lowering elevated cholesterol levels through lifestyle changes and drug treatment remains crucial for the prevention of heart attacks and strokes, said Jeffrey L. Probstfield, MD, a member of the ALLHAT steering committee and a professor of medicine and epidemiology at the University of Washington Health Sciences Center in Seattle.

ADDITIONAL INFORMATION:

Study details

Key design features of ALLHAT, the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, a five-year study:

The randomized, double-blind trial included more than 42,000 participants age 55 and older who had hypertension measuring at least 140/90 mm Hg. All had at least one other risk factor for heart disease, such as smoking or type 2 diabetes.
The researchers made an effort to recruit a variety of participants. About 47% were women, 47% were non-Hispanic whites, 32% were blacks and 36% had diabetes.
The study was conducted at 623 clinical sites in the United States, Canada, Puerto Rico and the Virgin Islands. About 7,000 participants were treated at Veterans Affairs clinics.