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Are you on the right blood-pressure medication?

The longer I practice medicine, the more I am dumbstruck by the schism between which medications and therapies really work, and the medicine most commonly practiced. "Evidence-based medicine" denotes doing only what has been clinically proven to work, and it's become a rallying cry for improving health care. But evidence-based medicine breaks down when you're not keeping up with the evidence.

Take beta blockers, for example. They're not part of an offensive football scheme; they're one of the four major classes of drugs used to treat hypertension (high blood pressure). They act by slowing the heart rate and by dilating blood vessels, thereby lowering blood pressure. The logic behind using beta blockers is simple: Hypertension causes strokes and heart attacks, so lowering blood pressure back into the normal range should prevent strokes and heart attacks.

It hasn't worked out that way for beta blockers. Yes, they do lower blood pressure, but they have other side effects — weight gain, promotion of diabetic changes, and unfavorable changes in cholesterol — that seem to negate the benefits of hypertension control.

For hypertension alone, evidence isn't there
Beta blockers have their place: They do improve the lives of patients with known coronary artery disease or heart failure. But for treatment of hypertension alone, the evidence just isn't there.

A recent article in the Journal of the American College of Cardiology reviewed nine studies involving 34,000 patients taking beta blockers for hypertension alone. The authors concluded that in contrast to patients with heart attacks and heart failure, where the heart-rate-slowing effects of beta-blockers are clearly beneficial, "beta-blocker-associated reduction in heart rate increased the risk of cardiovascular events and death for hypertensive patients." All the hassle and cost of taking a pill every day, and it increases your risk of dying?

The large majority of those included in the analysis were taking the beta blocker atenolol, which, according to an accompanying editorial in JACC, was the fourth most prescribed drug in the United States in 2005.

Certainly, some of the 44 million prescriptions filled that year were for patients with heart disease or heart failure; but just as certainly, some were for the treatment of hypertension alone.

Dr. Richard Grimm, a professor of cardiology and epidemiology at the University of Minnesota School of Medicine, is familiar with the evidence against beta blockers. As director of the Berman Center for Outcomes and Clinical Research in Minneapolis, he's been involved in numerous national hypertension drug trials, including ALLHAT, the largest hypertension clinical trial ever performed.

Studies on diuretics show benefits
Grimm has also served on several Joint National Committees (JNC), a group of clinical experts that make periodic best-of-practice recommendations through the National Heart Lung and Blood Institute and the National Institutes of Health. He remembers being on a JNC in the early '80s, deciding which drugs to recommend and in what order. "Diuretics were clearly the choice at the time because studies have been done with them showing a lot of benefit," Grimm recalled.

"But the benefits of beta blockers weren't there then, and they're not there now."

In the ALLHAT study that the Berman Center participated in, beta blockers were one of the drugs that could be used if the first drug wasn't controlling the blood pressure. "But there wasn't any evidence that the beta blocker made any difference one way or the other in terms of the primary drug comparisons."

"So I've never really been a huge fan of beta blockers unless there's some other reason to use them, like for patients who have angina or heart failure or something like that." Grimm noted that current British and European guidelines have pushed beta blockers to third tier, and he expects the next JNC recommendations to follow suit.

So here comes the obvious question: Why do physicians keep prescribing beta blockers for hypertension alone? 

"Doctors are creatures of habit," Grimm responded. "They are also creatures of marketing. Once they get started using something and they get comfortable, it's hard to get them to change. Beta blockers were really the first drugs that came in after diuretics that were tolerated well, and so they had a foot in the door in terms of use."

A foot in the door should never suffice for evidence-based medicine, but there you have it.

70 million Americans have hypertension
Grimm points out that about 70 million Americans have hypertension, defined as a blood pressure 140/90 or higher, and another 70 million are just about there. From a physician who's spent a good part of his career studying the treatment of hypertension, here's Grimm's message to those masses.

"What's important is to make sure your blood pressure is lower. You can do that through lifestyle — weight loss is a great way to do it, sodium reduction also — but most people can't do that. And then you can use medication, and most people need two drugs to really control their blood pressure. Diuretics, in terms of cost and side effects and amount they lower blood pressure, are the best performers, and I'm sure the JNC 8 will come out and say that they probably should be the first drug used."

Tired of taking your blood pressure medication? Need a little incentive? Here's a pill that's easy to swallow: By Grimm's calculations, a drop of 4 mmHg in blood pressure lowers the risk of having a heart attack by 25 percent.

You can read the JNC 7 Recommendations Reference Card here (PDF).

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