Map of life expectancy at birth from Global Education Project.

Monday, March 31, 2008

There are two sources of BS

There's been plenty of coverage of the results of the so-called ENHANCE study that casts doubt on the effectiveness of Vytorin in preventing atherosclerosis, but very little of it, as far as I can tell, casts much light on the public health policy issues behind this latest debacle. (Vytorin is a combination of a statin, the traditional cholesterol-lowering agents, and ezetimibe, a chemical that blocks absorption of cholesterol from food.) In fact, the stories tend to appear in the business section, where the emphasis is on what's going to happen to Schering-Plough stock. Here are a few things the corporate media isn't telling you.

First of all, if you have watched television for even one hour in the past year, you have probably failed to escape the advertisements for Vytorin, one of the drugs most heavily marketed to consumers in all history. Those are the ads with people dressed up to look like food, and the line that "There are two sources of cholesterol: the food you eat, and that produced by your body based on family history." You are urged to take Vytorin because it addresses both of these sources.

Okay, aside from the observation that there is no reason why looking at pictures of people dressed up to look like lasagna and chocolate cake should cause you to take a pill, you need to know that the information in the advertisement is false. It is true that your body produces cholesterol, and that you do get some cholesterol from the food you eat. However, it is not true that the cholesterol produced by your body is "based on family history." You do have a genetic predisposition to produce more or less LDL (the "bad" cholesterol), but that is not "based on family history."

Family history has some correlation with your blood lipid profile, but it does not determine it. First of all, you may or may not have inherited any of the particular genes that your mother or father had that influence cholesterol levels. Family history may give some indication of your likely genetic profile, but it is not identical with it. Second, and more important, your genes don't determine your LDL cholesterol level or anything else about you for that matter, they interact with your environment to make you what you are. Diet is an important determinant of your blood lipid profile, but it is not, in fact, ingestion of cholesterol that is the most important factor. Rather, it's the kinds of ordinary fats that you eat, which influence production of LDL and HDL cholesterol in the liver.

In case you didn't already know -- and most readers of this blog do know, I'm sure, not least because I've written about it a lot -- the more saturated fat you eat, and even worse, the more trans-unsaturated fat you eat, the worse off you will be. That means mostly animal fat from meat and dairy, and artificially hydrogenated vegetable oils. Unsaturated vegetable oils, and particularly mono-unsaturated oils such as olive oil, are the good fats. Dietary cholesterol is most likely to come from eggs, by the way, but it's less important in raising LDL cholesterol than saturated and trans fats.

So, the ads are misleading because they are trying to make you think that by taking Vytorin, you are eliminating the influence of diet on your cholesterol levels and making it okay after all to eat stuff your doctor told you to cut down on. To put it another way, they are lying to you, in order to sell you a product, and the result may very well be to influence your behavior to your detriment, specifically with the effect of causing you to have a heart attack or a stroke. That's kind of evil, don't you think? And don't you think the FDA should have said something to Schering-Plough about those misleading ads?

Then there's the question of why this drug was approved in the first place. It was approved based on a 12 week trial with fewer than 4,000 patients. There has never been any evidence whatever that ezetimibe (Zetia), the stuff that blocks cholesterol absorption from the gut, has any health benefit whatsoever. The trial showed that combined with a statin, it does produce an additional reduction in LDL cholesterol, and that was enough for the FDA. The ENHANCE trial, however, shows that it does not produce a concomintant slowing of the progression of atherosclerosis. (Actually, there's a trend toward making it worse, but it is considered not statistically significant.) We'll have to await even longer-term studies to learn if it has any benefit on heart disease and stroke outcomes, but at this point, there's no reason to believe that it will.

Now here's the bottom line -- the stuff costs a whole lot of money, all of which, it now appears, has been wasted. NEJM, which I am coming to like more and more as they are changing their evil ways and showing a genuine commitment to the public welfare, makes this important study available free to you, the great unwashed. Dr. Jackevicius and her colleagues find that by 2006, 3.4% of prescriptions for lipid lowering agents in Canada were for Ezetimibe, while more than 15% of prescriptions in the U.S. were for Ezetimibe. In the U.S., prescriptions for statins actually fell since the introduction of Ezetimibe. And, we spent 4 times as much per capita on this apparently useless or even dangerous potion than did the Canadians -- a total of more than $260 million a month.

So why did the hoseheads of the Great White North escape our fate? Well, for one thing, Direct to Consumer advertising of prescription drugs is forbidden in Canada. They spent $200 million a year on those ads here in the land of the free, which obviously paid off big time. Second, as you may have heard, Canada has single payer health care and Vytorin and eztemibe were approved for use in most Canadian provinces only as a last resort, because data on outcomes were not available. Unlike doctors here, Canadian docs can't just write prescriptions because the customer saw it on TV -- they have to follow guidelines.

So maybe we are the Greatest Country on Earth, and maybe Canada smacks of creeping socialism, but they are just maybe smarter than we are.

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