News - Hypertension Week of Feb. 16, 2003/ Vol. 2 No. 07

Superiority of Diuretics for Treating Hypertension Disputed

A leading hypertension expert is disputing conclusions from a recent study that found that diuretics are superior to ACE inhibitors and calcium channel blockers in lowering blood pressure.

Writing in the February issue of the Journal of Clinical Hypertension, Dr. Michael Weber said the conclusions of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) are "debatable at best."

"Serious questions have arisen not only to the accuracy of the original claims, but also as to the propriety of announcing them in so flamboyant a fashion," said Weber, former president of the American Society of Hypertension.

The study results appeared in the Dec. 18, 2002 issue of the Journal of the American Medical Association (See Medical Week, Dec. 22, 2002).

Weber said the primary end point result, which was heart attacks, was conveniently omitted from the ALLHAT study conclusions. He noted that a secondary end point of stroke was contentious and may be explained by the design of the trial itself.

"The results of the study showed that for the formal primary end point of fatal coronary heart disease and nonfatal myocardial infarction, there were no meaningful differences among the drugs," Dr. Weber said. "In an almost unprecedented departure from scientific probity, the authors of the ALLHAT report omitted this apparently inconvenient fact from their conclusion."

Weber said the main basis for the conclusion that the diuretic was superior depended on secondary end points, most notably the stroke rate. Dr. Weber said stroke event rates were actually 7% lower in the calcium channel blocker group compared with the diuretic, a result that was not statistically significant. He added that the diuretic reduced the stroke event rate by 15% when compared with the ACE inhibitor.

The design characteristics of ALLHAT, according to Weber, made it probable that patients assigned to the ACE group would be exposed to both a blood pressure disadvantage as well as to suboptimal treatment combinations that predictably could increase their risk of events.

Weber said ALLHAT trial participants received beta-blockers and other medications if they did not respond to their primary drug. He said this helped the diuretic group as a beta-blocker and diuretic provides a logical and effective blood pressure lowering combination. However, adding a beta-blocker to an ACE is far less helpful.

Weber did not dismiss the value of using diuretics to treat high blood pressure in combination with other drugs and as a first-step treatment in the elderly, particularly in black patients.

"No doubt thiazide diuretics are relatively inexpensive, at least as far as the cost of acquisition is concerned, but so are other antihypertensive agents," Dr. Weber concluded. "Most importantly, we all now recognize that effective blood pressure control in most hypertensive patients calls for logical drug combinations that typically will include all the drug types examined in ALLHAT as well as other classes."

Dr. Weber urged members of the National Heart, Lung, and Blood Institute, which was responsible for ALLHAT and for appointing members to the committee writing national hypertension treatment guidelines, to "thoughtfully take into account the broad array of clinical trials data, including responsible interpretation of ALLHAT, that are now available."

Other sources: Journal of Clinical Hypertension