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Blood Pressure Drugs for All at High Risk, Whether or Not Blood Pressure is High

Posted by medconsumers on June 1, 2009

The typical doctor visit starts with blood pressure measurement, and everyone with a high reading is told to come back again in three months. If blood pressure remains high, one drug or more is the next step, and then three-month follow-up visits continue indefinitely.

A team of British researchers wants to radically change this scenario. Blood pressure lowering drugs should be prescribed to anyone who is at high enough risk to benefit from treatment, whatever their reason for being at high risk and regardless of whether they have high blood pressure or not. What’s more, the British researchers want to change the traditional doctor-visit focus from: has your blood pressure gone down and stayed down? to: is your drug therapy causing any adverse effects?

All blood pressure drugs can dramatically reduce the risk of heart attack and stroke; and all are virtually interchangeable, say the British researchers. Therefore, any tailoring to the needs of the individual would be based on whether the drugs cause adverse effects. Fewer doctor visits would be the result, as well as fewer adverse drug reactions, many of which are currently caused by doses that are too high. Eliminated is the uncertainty many doctors have about which drugs to prescribe and who should be treated.

The proposed radical shift in thinking about blood pressure drugs appeared online last month in the British Medical Journal. Malcolm Law and colleagues based their proposal on an in-depth analysis of the data from 147 blood pressure drug trials published between 1966 and 2007. The trials had a combined total of nearly a half-million participants, aged 60 to 69 years.

Law and colleagues base their conclusions on these trials that compared people with and without heart disease given drugs or a placebo; people with normal blood pressure and high blood pressure (hypertension) with and without drug therapy.  All five classes of blood pressure drugs were represented, as well as differing doses.

Here’s what they found: Any one of the main classes of blood pressure drugs given at the standard dose will reduce the incidence of fatal and non-fatal heart attack by about 25% and stroke by about 33% and heart failure by about 33%. These reductions held up, say Law and colleagues, whether or not the people had heart disease and whether or not they had high blood pressure.

Of course, you would want to know what your risks are for each heart problem if you don’t take any drugs so you can get a clearer idea of what the risk becomes once you do. The British researchers did the math for you based on older people living in England and Wales. At age 65, the risk of having a heart attack (fatal and non-fatal) in the next ten years is about 10% in men and 5% in women. If they go on blood pressure drugs at half dose, the risk in men goes down to 5.4% and in women to 2.7%.

Adverse effects will be minimized with low-dose combination therapy. Cost is dismissed because four of the five drug classes are off patent, and the fifth (angiotensin receptor blockers) will be off patent by the end of this year. “It is difficult to defend the widespread practice of tailoring treatment. The case for individualizing blood pressure lowering disappears with low dose combination therapy based on three drugs; the greater efficacy compared with selective monotherapy or dual therapy avoids the need to choose between drugs,” wrote Law and colleagues.

Some exceptions were found to the all-drugs-are-equally-effective finding. For example, beta blockers [some brand names: Tenormin, Toprol] have an edge over other drugs when given after a recent heart attack; and calcium channel blockers are less effective than other drugs in the risk of heart failure but they had a greater stroke prevention effect than other drugs. Some drugs should be avoided in pregnancy.

Two of its co-authors, Malcolm R. Law and Nicholas J. Wald, made headlines six years ago when they proposed something similar in concept called the polypill. The polypill combines three blood pressure drugs at half the standard dose, a statin, folic acid, and aspirin. At the end of their new research paper, Law and Wald acknowledged that they had “competing interests” (i.e., conflicts of interest) because they hold patents “on the formulation of a combined pill to simultaneously reduce four cardiovascular risk factors, including blood pressure.”

Their research paper is bound to reignite a worldwide debate among doctors about the use of drugs for prevention. What’s needed now is the release of all data used in the new meta-analysis of blood pressure lowering drugs so that an additional critical analysis can be conducted by a team of researchers without competing interests.

There may be strong reasons against the idea that the benefits outweigh the risks for everyone on blood pressure drugs. For starters, the implication that adverse drug effects are banished with low doses has already been disproved in low-dose aspirin studies. No matter how low the dose in these studies, the cases of gastrointestinal bleeding are higher in the people taking low-dose aspirin than in the people taking a placebo. This is true of the Women’s Health Initiative in which the study participants were taking only 100 mg aspirin every other day.

For more information
The May 19, 2009 issue of the British Medical Journal “Use of blood pressure lowering drugs in the prevention of cardiovascular disease: meta-analysis of 147 randomized trials in the context of expectations from prospective epidemiologic studies.”

Maryann Napoli, Center for Medical Consumers© June 2009

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