UW News

May 20, 2003

Low-dose diuretics are the most effective way to treat hypertension, according to analysis of 42 studies

An analysis of clinical trials involving more than 192,000 patients with hypertension shows that low-dose diuretics are more effective at preventing cardiovascular health problems than any other blood-pressure medication, according to University of Washington researchers and colleagues.

Their study will be published in the May 21 edition of The Journal of the American Medical Association.

The in-depth study of other studies — called a meta-analysis — examined clinical trials to see which treatments were associated with reduced risks of heart attacks, strokes, heart failure and death. The 42 clinical trials had a combined total of 192,478 patients followed for an average of three to four years. The studies compared various combinations of placebo, diuretics, angiotensin converting enzyme (ACE) inhibitors, beta-blockers, calcium-channel blockers and other medications.

“This analysis provides compelling evidence that low-dose diuretics are the most effective first-line treatment for preventing cardiovascular disease morbidity and mortality,” says Dr. Bruce M. Psaty, lead author of the study and a professor of medicine, epidemiology and health services and co-director of the UW’s Cardiovascular Health Research Unit.

Since 1993, low-dose diuretics and beta-blockers have been recommended as first-line drug therapy for hypertension by the U.S. Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure.

Many studies have been conducted since then; Psaty said the current report was inspired because the various trials, which used many different treatments and comparisons, have created “a patchwork” of evidence about the health benefits of antihypertensive agents. This study used a new method, called network meta-analysis, to synthesize all the available evidence on the health effects of various treatments for high blood pressure.

“The network meta-analysis allows us to view the totality of evidence, instead of comparing one pair of treatments at a time,” said co-author Dr. Thomas Lumley, an assistant professor of biostatistics in the UW School of Public Health and Community Medicine.

Low-dose diuretics were significantly better than each of the other blood-pressure medications for preventing at least one major cardiovascular outcome. No other medication was significantly better than low-dose diuretics for preventing any cardiovascular outcome.

To be eligible for the meta-analysis, the studies had to be randomized, controlled trials that evaluated major cardiovascular disease end points in hypertensive patients for at least a year. Cardiovascular disease end points include heart attack, stroke and death.

“If you are on treatment for high blood pressure, and if you are not taking a low-dose diuretic, it is reasonable to ask your physician, ‘Why not?,'” Psaty says.

This study was funded by grants from the National Heart, Lung, and Blood Institute and the American Heart Association.

Other authors of the paper are Gina Schellenbaum and Dr. Noel Weiss, Department of Epidemiology in the UW School of Public Health and Community Medicine; Dr. Curt Furberg and Dr. Marco Pahor, both at Wake Forest University School of Medicine; and Dr. Michael Alderman, Albert Einstein College of Medicine, New York.