FRIDAY, Oct. 23, 2009 (HealthDay News) -- Adding an angiotensin receptor blocker (ARB) drug to help control blood pressure has no benefit for people with heart disease who already are taking an ACE inhibitor, a new study finds.
The so-called "meta-analysis" of 41 previous studies found that combination therapy seems no better than ACE inhibitor therapy alone and may be harmful.
Results of the study, funded by the U.S. Agency for Healthcare Research and Quality, were published in the Oct. 20 issue of Annals of Internal Medicine.
"The question is whether you are going to provide more benefits to patients by adding an ARB," said Jean Slutsky, director of the AHRQ Center for Outcomes and Evidence, which commissioned the study. "From this study, it appears that it doesn't seem to actually improve care."
It's a finding with financial as well as medical implications. Millions of Americans now take ACE -- angiotensin converting enzyme -- inhibitors to control high blood pressure. ARBs, which have become increasingly popular in recent years, tend be more expensive, since many ACE inhibitors are available as generic drugs while ARBs generally are not.
Both classes of drugs lower blood pressure by their effect on angiotensin II, a molecule that tightens arteries. ACE inhibitors attempt to prevent formation of angiotensin II, while ARBs block the cell receptors through which they act.
The new study was one of a series done to improve the effectiveness of health care in the United States, Slutsky said. "There was some uncertainty about the effectiveness, benefits and harms of ACE inhibitors versus ARBs in this population" (people with known but stable heart disease), she said.
The analysis of the 41 trials examined in the study found that ACE inhibitors reduced the risk of death by about 13 percent for people whose cardiac problems did not include heart failure, and the risk of heart attack by about 17 percent. Adding an ARB drug did not reduce the risk further, but did increase the rate at which drug therapy was discontinued because of side effects such as fainting.
"We showed results similar to what they [the authors of the new study] did," said Dr. Sripal Bangalore, a fellow in interventional cardiology at Brigham and Women's Hospital in Boston, who published a similar meta-analysis a year ago. "Our study showed that the addition of an ARB to an ACE inhibitor did not give any benefit in terms of heart endpoint, unless in patients who had heart failure."
The lesson for doctors prescribing drugs for blood pressure control in people with stable heart disease is clear, Bangalore said: "Based on current studies, combination therapy should be avoided."
Current guidelines by organizations such as the American Heart Association already reflect that lesson. Guidelines generally recommend ACE inhibitors as a first-line therapy for high blood pressure.
More information
For more on high blood pressure and how to control it, visit the U. S. National Heart, Lung, and Blood Institute.
