Prospects bright for medical care that is tailored

Each year, about 1 million people in the U.S. have stents put in to treat clogged coronary arteries — a procedure some might not have needed, according to a recent study. Although stents relieve angina, they were found to be no more effective in eliminating the risks of heart attack, stroke or death than drug treatment alone.

Americans want to believe that modern medicine is sophisticated and evidence-based, but this study underscores how little we know when we make most medical decisions. Some of the pills and medical devices we depend on are used on the basis of evidence that is flimsy at best.

In medicine, there's a concept called "numbers needed to treat," or NNT — an estimate of how many patients use a drug or treatment compared to how many benefit from it. For treatments considered "effective," the NNT is typically between 30 and 80. That is, 30 to 80 people have to use a specific drug or device before one person actually will benefit. Doctors and researchers simply don't know which individuals will respond to what. So we treat as many people as possible in an attempt to benefit as many people as possible. But that can also backfire.

One of the most "effective" treatments in medicine is the implantable cardioverter defibrillator. This device, smaller than an iPod Nano, can sense a life-threatening abnormality in the heart's electrical rhythm and rapidly deliver a shock to restore normal rhythm.

There is only one problem. Out of every 100 patients who get this device permanently implanted, only 12 to 15 ever need it and receive an appropriate electrical discharge. The remaining 85 percent or more have a device that costs more than $50,000 to put in, carries a risk of infection and might "fire" inappropriately. More than 200,000 such devices are implanted in this country every year.

On the pharmaceutical side, statins are among the world's top-selling drugs, with more than $15 billion per year in prescriptions. These medicines lower the blood's "bad" cholesterol level. However, for every 100 patients who take a statin, only eight to 10 derive any real benefit in terms of reducing the risk of heart attack, stroke or death. The remaining 90 percent or so are taking an expensive medicine — a cost of $3 to $4 per day — with potential side effects. They gain the psychological comfort of a reduced cholesterol level but no real health value.

Likewise, the second most commonly prescribed medicine in our country is Plavix, taken to avoid blood clots. About 30 percent of patients do not respond to the common dosage and are left vulnerable to developing potentially lethal blood clots.