Spare the Cholesterol, Spoil the Diabetic
Evan David Rosen, M.D., Ph.D. Assistant Professor of Medicine,
Harvard Medical School
Patients
with diabetes usually know about the perils of high blood sugar, which
includes damage to the eyes, kidneys, and nerves. These are major issues,
and there is no more ardent supporter than I am of maintaining glucose
levels as close to normal as possible. The fact remains, however, that
people with diabetes are much more likely to develop and/or die from
cardiovascular disease than any of these other problems. Up to 80% of
type 2 diabetics will suffer a heart attack, stroke, or peripheral vascular
disease. In many cases, cardiovascular disease will result in significant
neurological damage, amputation, and even death.
These statistics demonstrate why it is critical for patients with diabetes
to maintain 'good vascular hygiene'. What is good vascular hygiene?
Three things: quitting smoking, reducing blood pressure, and keeping
cholesterol levels in check.
The cholesterol recommendation in particular has been around for a long
time—despite an absence of evidence on whether lowering cholesterol
works in diabetes. Surprisingly, lingering questions remain about cholesterol-lowering
in diabetes. Do patients with diabetes benefit as much as non-diabetics
from lipid lowering therapy? Which drugs are the best to use in diabetes?
What target level of cholesterol is appropriate?
To address these important issues, a committee of the American College
of Physicians (ACP) commissioned a review of the world's literature
on lipid lowering in type 2 diabetes. The ACP then used this information
as the basis for detailed, specific recommendations for patients and
their doctors. The ACP review looked at a large number of published
clinical trials—none of which, it is important to note, were specifically
dedicated to studying type 2 diabetics. All of the studies, however,
included at least some diabetics, and this allowed the ACP to essentially
lump together all the information from the diabetics in different studies
and assess their response to cholesterol-lowering therapy.
The studies were of two major types, known as primary prevention and
secondary prevention. In a primary prevention trial, researchers looked
for people who had not yet shown any sign of cardiovascular disease.
They then put these folks on a drug, or a placebo, and tested whether
the drug resulted in fewer cases of heart attack or stroke. When the
ACP looked at six, large, primary prevention studies, they found that
for every 34 patients with type 2 diabetes who were treated with cholesterol-lowering
meds for more than 4 years, one heart attack or stroke was prevented.
This may sound small, but compares favorably with many other disease
prevention strategies in common medical practice.
The secondary prevention trials were even more dramatic. Secondary prevention
is for people who have already had a heart attack or stroke. The goal
is to prevent a second episode. For people with type 2 diabetes known
to have cardiovascular disease, there was a highly significant benefit
to treating with lipid-lowering therapy. This seems to be true regardless
of what level of cholesterol you start out with. For every 14 such patients
treated for 5 years, one cardiovascular event was prevented.
These findings led the ACP to the following four recommendations:
1. All men and women with type 2 diabetes and known cardiovascular disease
should be on lipid-lowering therapy. The drugs with the most proven
efficacy are members of the statin class, including Lipitor™,
Pravachol™, Zocor™, Mevacor™, and others. At least
one study suggests that an alternative lipid-lowering drug, Lopid™,
might be useful in diabetic patients with low levels of both LDL and
HDL cholesterol.
2. For patients with type 2 diabetes who are not known to have cardiovascular
disease, a statin should be used to reduce cholesterol levels, especially
if there is another cardiovascular risk factor. This means that if you
have type 2 diabetes and any one of the following conditions, you should
be taking a statin: age greater than 55, high blood pressure, smoking,
or dysfunction of the left side of the heart. That ends up covering
most people in the average adult type 2 diabetes clinic.
3. Don’t skimp on the statin! Patients should be taking at least
moderate doses of these drugs. This translates to daily doses of Pravachol™
(40 mg), Mevacor™ (40-80 mg), Zocor™ (40 mg), and Lipitor™
(20 mg).
4. Finally, there has been a lot of hype about the potential side effects
of statins, including muscle and liver damage. In fact, more people
are hurt by NOT taking these drugs than by taking them. In fact, it
is no longer recommended that patients even be monitored for liver and
muscle enzyme levels while on statins (except in specific cases). This
includes the rare cases where symptoms of jaundice or muscle pain develop
while taking the drug, elevated levels of these enzymes are discovered
before taking the statin, or in cases where other drugs are also being
used that are known to damage the muscle and liver
In case you haven't noticed, there are no specific recommendations about
any particular "magic number." There is no cholesterol number
above which one would automatically treat with drugs, and no target
level at which one could be satisfied that the cholesterol was low enough.
Several studies have shown that reducing cholesterol levels as low as
possible may confer additional benefit. In other words, it's not clear
that we know how low is low enough, and at present, there appears to
be little downside (other than cost) for using higher doses of statins
than we all previously thought were good enough.
The bottom line is this: The majority of people with type 2 diabetes
should be taking a statin, and a pretty decent dose at that. This is
not a substitute for good glucose control, but an incredibly important
adjunct therapy that will save a lot of lives.
Viewpoint is an editorial column that expresses the opinion of the specific
Medical Director, who is solely responsible for its content. Viewpoint
does not represent the views or opinions of Veritas Medicine and does
not reflect the opinions of other physicians and researchers.
References
Snow V, Aronson MD, Hornbake ER, Mottur-Pilson C, Weiss KB; Clinical
Efficacy Assessment Subcommittee of the American College of Physicians.
Lipid control in the management of type 2 diabetes mellitus: a clinical
practice guideline from the American College of Physicians. Annals of
Internal Medicine. 2004 Apr 20;140(8):644-9.
Written by Evan D. Rosen, M.D., Ph.D.
Content created 5/7/04
Content last reviewed May 7, 2004
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