jeudi 17 janvier 2008

When medical conventional wisdom is wrong

Yesterday I wrote about an editorial in the New York Times that focused on the delay in publishing the results of a study of two new cholesterol-lowering drugs -- results that showed the drugs' ineffectiveness in lowering the risk of heart attacks and strokes.

Today the paper has an article revealing that the entire conventional wisdom about cholesterol -- conventional wisdom that is making a ton of money for pharmaceutical companies in the form of statin drugs -- may be wrong:

For decades, the theory that lowering cholesterol is always beneficial has been a core principle of cardiology. It has been accepted by doctors and used by drug makers to win quick approval for new medicines to reduce cholesterol.

But now some prominent cardiologists say the results of two recent clinical trials have raised serious questions about that theory — and the value of two widely used cholesterol-lowering medicines, Zetia and its sister drug, Vytorin. Other new cholesterol-fighting drugs, including one that Merck hopes to begin selling this year, may also require closer scrutiny, they say.

“The idea that you’re just going to lower LDL and people are going to get better, that’s too simplistic, much too simplistic,” said Dr. Eric J. Topol, a cardiologist and director of the Scripps Translational Science Institute in La Jolla, Calif. LDL, or low-density lipoprotein, is the so-called bad cholesterol, in contrast to high-density lipoprotein, or HDL.

For patients and drug companies, the stakes are enormous. Led by best sellers like Lipitor from Pfizer, cholesterol-lowering medicines, taken by tens of millions of patients daily, are the largest drug category worldwide, with annual sales of $40 billion.

Despite widespread use of the drugs, though, heart disease remains the biggest killer in the United States and other industrialized nations, and many people still have cholesterol levels far higher than doctors recommend.

As a result, drug companies are investing billions of dollars in experimental new cholesterol-lowering medicines that may eventually be used alongside the existing drugs. If the new questions result in slower approvals, it would be yet another handicap for the drug industry.

Because the link between excessive LDL cholesterol and cardiovascular disease has been so widely accepted, the Food and Drug Administration generally has not required drug companies to prove that cholesterol medicines actually reduce heart attacks before approval.

They have not had to conduct so-called outcome or events trials beforehand, which are expensive studies that involve thousands of patients and track whether episodes like heart attacks are reduced.

So far, proof that a drug lowers LDL cholesterol has generally been enough to lead to approval. Only then does the drug’s maker begin an events trial. And until the results of that trial are available, a process that can take several years, doctors and patients must accept the medicine’s benefits largely on faith.

“You’ve got a huge chasm between F.D.A. licensure and a clinical events trial,” said Dr. Allen J. Taylor, the chief of cardiology at Walter Reed Army Medical Center.

Nonetheless, the multistep process has worked well for several cholesterol drugs — including Lipitor and Zocor, which are in a class of drugs known as statins. In those cases, the postapproval trials confirmed that the drugs reduce heart attacks and strokes, adding to confidence about the link between cholesterol and heart disease.

Doctors generally believe that the amount by which cholesterol is lowered, not the method of lowering it, is what matters.

That continues to be the assumption of Dr. Scott M. Grundy, a professor of medicine at the University of Texas Southwestern Medical Center who was the chairman of a panel in 2001 that set national guidelines for cholesterol treatment.

“LDL lowering, however it occurs, delays development of coronary atherosclerosis and reduces risk for heart attack,” Dr. Grundy said this week. In atherosclerosis, plaque builds up in the arteries, eventually leading to blood clots and other problems that cause heart attacks and strokes.

In the last 13 months, however, the failures of two important clinical trials have thrown that hypothesis into question.


More here.

The unstudied wild card in the study of health risks in America is the impact of stress. Whether stress causes obesity directly by spurring release of an excess of cortisol, or if, as a 2003 study suggests, cravings for fats and carbohydrates that often accompany stress cause a reduction in the secretion of stress hormones, remains to be seen. The role of inflammation in maladies such as heart disease and diabetes remains under-studied. Conventional wisdom, for example, is that obesity leads to diabetes. But with one-third of Americans being defined as obese, with only seven percent being diabetic, perhaps the connection made by the medical profession is backwards.

It's easier for the bedrock of American society for so-called "lifestyle diseases" to be blamed on personal behavior. If you have heart disease, it's because you eat too many spare ribs. If you have diabetes, it's because you stuff yourself with sweets. If you are overweight it's because you're a glutton. When the notion that we can't afford health care for everyone is discussed, there's always an undercurrent of people with these diseases don't "deserve" health care because "they brought it on themselves."

But what if they didn't?

What if the cause of these diseases, and even the cause of obesity, is the stress of living in a country where consumption is the primary virtue, that has a diminishing job base, and where your willingness to devote your every waking hour to work is a benchmark of how valuable you are as an employee?

It's well-known that Americans receive and take less vacation time than their peers in the rest of the developed world. As jobs become less secure, Americans are even less inclined to take time off, lest their employers decide that they aren't really necessary. It's gotten worse over the last seven years, where people who used to earn a living salary at one job are now trying to cobble an income together working multiple jobs. Remember the single mother who told George W. Bush in 2005 that she works three jobs, and he said it was "fantastic":

"You work three jobs? … Uniquely American, isn't it? I mean, that is fantastic that you're doing that...do you get any sleep?"


That isn't just a Bushism, it's Republican policy. Minnesota wingnut Michelle Bachman said just the other day:

I am so proud to be from the state of Minnesota. We’re the workingest state in the country, and the reason why we are, we have more people that are working longer hours, we have people that are working two jobs.


Yup...working two jobs just to eke out an existence is a great and wonderful thing. Too bad Congressional Republicans don't do the same.

Is it an accident that obesity rates have skyrocketed in recent years and heart disease remains the biggest killer in the country at the same time as Americans feel less secure about their futures? Even those who are still drinking the Republican kool-aid about the economy still obsess about the Scary Brown Men from the Middle East who are coming to kill them. After all, the fear of terrorism causes its own brand of stress.

But of course it's easier to stuff people with statin drugs and blame them for their own health problems than to examine the stresses in the culture in which we live and perhaps make changes to the workplace and the community that might reduce the stress that may be the single greatest contributor to so-called "lifestyle diseases".

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