One more post about cholesterol and I promise to lay off for a while.
Sharon Begley has written a great article for the Saturday Evening Post:
http://www.saturdayeveningpost.com/2012/04/24/wellness/cholesterol-conundrum.html
--reviewing the data showing the lack of benefit when statins are taken for primary prevention of cardiovascular disease, and especially going into the "number needed to treat" as a helpful statistic. Along the way she reviews the various adverse reactions associated with statins--diabetes, memory loss as well as muscle aches--and adds a recent study suggesting that if you take a statin and then exercise, your body's ability to repair muscle is reduced. (A wonderful way to prevent heart disease--make it harder to exercise.)
The article says so many good things that it seems petty to pick out one problem, but I was disappointed that Begley (apparently to try to make clear that she was not simply bashing statins for bashing's sake) gave the drugs credit for the marked decrease in deaths from heart disease over the last 3 decades in the US. No one I know of says that drop was due to statins and most believe it primarily related to lifestyle changes and maybe a bit related to better outcomes in the acute care of heart attacks.
Now, you might wonder, if all this is so, then how come the drug industry has been able to convince us to get so crazy about measuing everyone's cholesterol (even kids) and then precribing statins at the first hint of a high measurement? (Begley starts off with the very sensible observation, that if what we know about statins and primary prevention is indeed true, then most of the justification for doing screening cholesterol measurements goes out the window.) The possible answer to that question is contained in a recent article that addresses the "cholesterol myth." While the article itself tends to go overboard in recommending somewhat extreme nutritional approaches, the core message is worth making note of.
Dr. Duncan Adams of New Zealand recently wrote about the "Great Cholesterol Myth":
http://qjmed.oxfordjournals.org/content/104/10/867.long
The way Dr. Adams tells the story, Brown and Goldstein won the Nobel Prize for their discovery about the relationship between high cholesterol and heart disease. They were studying a very special population of patients--those with the gene for familial hypercholesterolemia, whose cholesterol levels are sky-high and who often develop premature heart attacks and vessel disease. Brown and Goldstein assumed that what they were seeing was cause and effect-- high cholesterol levels in the bloodstream cause the vessels to have defects. Dr. Adams marshals arguments that they had it backwards. What if the basic defect in the vessel disease seen in this select group of patients is super-brittle vessel walls? What if cholesterol makes vessel walls flexible? (After all, cholesterol is an essential chemical and we'd die if we had none of it in our bodies.) What if the genes these patients inherited make their vessel walls unable to absorb cholesterol, so they become brittle, and the unabsorbed cholesterol then floats around in the bloodstream?
Dr. Adams' theory shows how by studying a very select group, and then generalizing to the entire population, we could have ended up with the wrong idea about cholesterol as a cause for cardiovascular disease. (Begley explains why it turns out that cholesterol levels by themselves are a very weak predictor of heart attack risk.) Going from what's true of a person with a total cholesterol level of 500, and assuming the same thing is true for a person with a cholesterol of 201, is exactly how drug company marketing prospers.
Can we know for sure that Dr. Adams' hypothesis is correct and that the "majority" view of cholesterol is wrong? Hardly. But it's worth knowing that out there is a potential, logical explanation that could show why we're quite confused in our thinking of how to prevent heart disease. (Hat tip to Jerry Hoffman and Rick Bukata for pointing out the Adams paper.)
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6 comments:
Thanks for this great series of blogs on the statin controversy. Ironically, the Lyon Diet Heart study which compared the Mediterranean Diet to the AHA "prudent" diet in people who had survived MI found better results than any statin trial: 56% relative risk reduction in total mortality, 65% relative risk reduction in cardiac mortality, 70% relative risk reduction in MI and even a 61% relative risk reduction for incident cancer. Without side effects! Granted that was secondary prevention. But Big Pharma doesn't make money from the diet, and no one is sending hordes of reps into docs' offices pushing it. Barbara Roberts, MD
Howard
Brown and Goldstein did not win the Nobel Prize for discovering the relationship between cholesterol and heart disease. They won the Nobel Prize for their discoveries relating to cholesterol metabolism.
Marilyn
Thank you for continuing to write on this subject! I don't think there is too much but rather too little. Far too many doctors still adhere to the lipid hypothsis and advocate statins for almost everyone. I don't know when the truth about statins in going to hit the mainstream. In the meantime, many people are continuing to be hurt by these drugs...
I think it is important to distinguish between "no benefit," "small, clinically insignificant benefit," and "clinically significant benefit." If statins had no benefit in primary prevention, the NNT would not be high, it would be infinite. Also, there is not one level of benefit (or, if you prefer, NNT) for primary prevention. There is a spectrum of benefit, just as there are people whose 10-year risk is less than 1% and people whose 10-year risk exceeds 20% who do not have known vascular disease.
Moreover, there is no magic level of benefit at which statins become appropriate. The reason being, that whether to take a statin is a personal decision which should hinge on the patient's individual characteristics and preferences. It is question for shared decision making.
Thanks for this great series of blogs on the statin controversy
most believe it primarily related to lifestyle changes and maybe a bit related to better outcomes in the acute care of heart attacks.
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