Publicity about Recent Studies on the Cholesterol-lowering Statin Drugs: Misinterpretations
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There
has been an extraordinary amount of news attention focused on recent studies concerning statins and heart disease, presented
at the American College of Cardiology meetings in March and, in one case, published in the April 8, 2004 New England Journal
of Medicine.
Without
disparaging the importance of the studies themselves, we believe that spin-doctors and a scientifically uncritical news media
have interpreted and stretched the findings in ways that go far beyond the actual data from the studies. A few examples will
illustrate this:
Misinterpretation
#1
Statins will prevent heart disease even in people who have not yet had a heart attack, stroke, angina or other kinds
of cardiovascular disease if they have elevated cholesterol levels. |
These recent studies are so-called secondary prevention studies. That is, the drugs were
given to people who, in the case of one study, had been hospitalized with an “acute coronary syndrome,” meaning
either a heart attack or high risk unstable angina.
{WEAK EVIDENCE FOR STATINS FOR THOSE WITH ONLY HIGH CHLOSTERAL}:
Although there are some earlier studies involving people without previous evidence of cardiovascular disease (angina,
heart attacks, bypass surgery, angioplasty or strokes), the evidence for treatment of these people, especially with cholesterol-lowering
drugs, is weaker and is known as primary prevention. This is especially
so for those people who do not have more than one of the risk factors listed below:
These
risk factors include hypertension, diabetes, smoking, obesity, or a close family history of premature heart attacks or strokes.
Other predisposing risk factors include a sedentary life style and a high-fat diet. It is likely that millions of people being
given cholesterol-lowering drugs such as statins for primary prevention do not have more than one of these risk factors and
are only being treated because of their total cholesterol or LDL cholesterol levels.
Thus,
it is extremely important to look at the global risk of cardiovascular disease rather than focusing on just the blood pressure
or just the cholesterol level. For primary prevention, it is usually most prudent to attempt to improve your cardiovascular
risk through sensible programs of diet and exercise.
A case
example of primary prevention involving someone who will, unfortunately, more times than not be recommended to start statins
follows:
Ben is
a 55-year-old man with a total cholesterol of 240 and an HDL of 50. However, his blood pressure is a normal 120/90 and he
is neither a diabetic nor does he smoke. Ben turns out to have a 5-year risk of having a cardiovascular event (heart attack,
stroke, etc) of only 5.1%, about one-half of the 5-year risk of over 10% that might merit drug treatment. It would be a good
idea for Ben — or most people, for that matter—-to adopt the non-drug approaches to lowering his cholesterol discussed
above, but since his global risk is as low as it is, drug treatment is not indicated even if his total cholesterol
and HDL cholesterol stay the same.
In summary,
these new studies did not even examine the role of statins in primary prevention. There are many people who have had
heart attacks and strokes with elevated cholesterol levels who are not being aggressively enough encouraged and helped to
lower their subsequent risk with diet, exercise or statins, the very kinds of secondary prevention the studies
did address.
Misinterpretation
#2
The study showed that atorvastatin (LIPITOR) prevents heart attacks. |
The study published in the New England Journal of Medicine was designed primarily to
see if the subsequent occurrence of a combination of adverse cardiovascular events was different in those taking a
high or “intense” dose of atorvastatin (LIPITOR) versus those using the “standard” dose of pravastatin
(PRAVACHOL). The combination included death from any cause, a heart attack, unstable angina (chest pain) requiring hospitalization,
bypass surgery or angioplasty, or a stroke.
It is
correct that the study showed that those taking atorvastatin were significantly (16%) less likely than those taking pravastatin
to have any of the above events — and this is an important finding. However, there was not a significant reduction in heart attacks alone, death alone, or in the combination
of death and heart attacks. The most significant reduction in the Lipitor group was in the subsequent occurrence of unstable
angina requiring hospitalization.
Misinterpretation
#3
The studies prove that atorvastatin (LIPITOR) is superior to pravastatin (PRAVACHOL). |
As mentioned
above, the purpose of the study was to see how intensive statin therapy (80 milligrams daily of atorvastatin) compared to
standard therapy (40 milligrams of pravastatin) in people who had already had a cardiovascular event. There is reason to believe
that the most important variable may be the intensity of the treatment rather than characteristics of the individual drugs.
Ideally,
the study should have explored both the different drugs and different doses — standard or intense — of each.
Cholesterol-lowering
Drugs For People 70 or Older
Aside
from these recent papers, there is still some misinformation about the evidence for treating — in the form of primary
prevention — elevated cholesterol levels in people over 70 years of age.
It is
clear that the relationship between moderately elevated cholesterol levels and increased risk of heart disease is not as clear
as people get older. As geriatricians Fran Kaiser and John Morely have written: “Given the uncertainty of the effects
of cholesterol manipulation in older individuals, what should be the approach of the prudent geriatrician to hypercholesterolemia
[elevated blood cholesterol levels]? In persons over 70 years of age, lifelong dietary habits are often difficult to change
and overzealous dietary manipulation may lead to failure to eat and subsequent malnutrition. Thus in this group minor dietary
manipulations such as the addition of some oatmeal [or other sources of oat bran or soluble fiber] and beans and modest increases
in the amount of fish eaten, may represent a rational approach. Recommending a modest increase in exercise would also seem
appropriate. Beyond this, it would seem best to remember that the geriatrician’s dictum is to use no drug for which
there is not a clear indication.”
The
use of cholesterol-lowering drugs in people 70 or older should be limited to patients with very high cholesterol levels (greater
than 300 milligrams) and those who manifest cardiovascular disease (previous history of heart attack or angina, stroke). More recent reviews of this topic have reached similar conclusions: In
one review, it was concluded that “unanswered questions include cholesterol treatment for primary prevention in the
elderly, gender effect, and benefit of treatment in persons older than 70.” There are even questions as to whether elderly
people who are hypertensive should have their cholesterol lowered by drugs. One review concluded that “Further trials
are required before routinely suggesting that it is advantageous to lower cholesterol in an elderly hypertensive who does
not have pre-existing evidence of coronary heart disease.”
What
You Can Do
If your
doctor recommends a cholesterol-lowering drug, especially for primary prevention, ask on what basis this is being done. This
is especially true if you either are over age 70 or have no more than one risk factor.