Meeting Cholesterol Level Guidelines Does Not Appear
to Lower Heart Attack Risk
Three of four hospitalized with heart attack had
good cholesterol levels indicating low risk; guidelines need revision?
Jan. 12, 2009 A stunning 75 percent of patients
hospitalized for a heart attack had cholesterol levels meeting national
guidelines that indicated they were not at high risk for a
cardiovascular event. Almost half had low-density lipoprotein (LDL)
cholesterol levels classified as optimal.
The new national study points to the need for
revision of these guidelines that indicated these victims were in the
safe zone. (See guidelines in box at lower right)
Specifically, these patients had low-density
lipoprotein (LDL) cholesterol levels that met current guidelines, and
close to half had LDL levels classified in guidelines as optimal (less
than 100 mg/dL).
"Almost 75 percent of heart attack patients fell
within recommended targets for LDL cholesterol, demonstrating that the
current guidelines may not be low enough to cut heart attack risk in
most who could benefit," said Dr. Gregg C. Fonarow, Eliot Corday
Professor of Cardiovascular Medicine and Science at the David Geffen
School of Medicine at UCLA and the study's principal investigator.
While the risk of cardiovascular events increases
substantially with LDL levels above 40 mg/dL, current national
cholesterol guidelines consider LDL levels less than 100 mg/dL
acceptable for many individuals. The guidelines are thus not effectively
identifying the majority of individuals who will develop fatal and
non-fatal cardiovascular events, according to the study's authors.
Researchers also found that more than half of
patients hospitalized for a heart attack had poor high-density
lipoprotein (HDL) cholesterol levels, according to national guidelines.
Published in the January issue of the American
Heart Journal, the study suggests that lowering guideline targets for
LDL cholesterol for those at risk for cardiovascular disease, as well as
developing better treatments to raise HDL cholesterol, may help reduce
the number of patients hospitalized for heart attack in the future.
"The study gives us new insight and intervention
ideas to help reduce the number of heart attacks," said Fonarow, who is
also director of the AhmansonUCLA Cardiomyopathy Center.
"This is one of the first studies to address lipid
levels in patients hospitalized for a heart attack at hospitals across
the entire country."
Study Database
The research team used a national database
sponsored by the American Heart Association's Get with the Guidelines
program. The database includes information on patients hospitalized for
cardiovascular disease at 541 hospitals across the country.
Researchers analyzed data from 136,905 patients
hospitalized for a heart attack nationwide between 2000 and 2006 whose
lipid levels upon hospital admission were documented. This accounted for
59 percent of total hospital admissions for heart attack at
participating hospitals during the study period.
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High Blood Cholesterol - What You Need to Know
By National Heart, Lung and Blood Institute
What Do Your Cholesterol Numbers Mean?
Everyone age 20 and older should have their
cholesterol measured at least once every 5 years. It is best to have a
blood test called a lipoprotein profile to find out your cholesterol
numbers. This blood test is done after a 9- to 12-hour fast and gives
information about your:
■ Total cholesterol
■ LDL (bad) cholesterol the main source of cholesterol buildup and
blockage in the arteries
■ HDL (good) cholesterol helps keep cholesterol from building up in
the arteries
■ Triglycerides another form of fat in your blood
If it is not possible to get a lipoprotein profile
done, knowing your total cholesterol and HDL cholesterol can give you a
general idea about your cholesterol levels. If your total cholesterol is
200 mg/dL* or more or if your HDL is less than 40 mg/dL, you will need
to have a lipoprotein profile done.
See how your cholesterol numbers compare to the
tables at top of this box.
HDL (good) cholesterol protects against heart
disease, so for HDL, higher numbers are better. A level less than 40 mg/dL
is low and is considered a major risk factor because it increases your
risk for developing heart disease. HDL levels of 60 mg/dL or more help
to lower your risk for heart disease.
Triglycerides can also raise heart disease risk.
Levels that are borderline high (150-199 mg/dL) or high (200 mg/dL or
more) may need treatment in some people.
What Is Your Risk of Developing Heart Disease or
Having a Heart Attack?
In general, the higher your LDL level and the more
risk factors you have (other than LDL), the greater your chances of
developing heart disease or having a heart attack. Some people are at
high risk for a heart attack because they already have heart disease.
Other people are at high risk for developing heart disease because they
have diabetes (which is a strong risk factor) or a combination of risk
factors for heart disease. Follow these steps to find out your risk for
developing heart disease.
>>
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Among individuals without any prior cardiovascular
disease or diabetes, 72.1 percent had admission LDL levels less than 130
mg/dL, which is the current LDL cholesterol target for this population.
Thus, the vast majority of individuals having their first heart attack
would not have been targeted for effective preventative treatments based
on the criteria used in the current guidelines.
The team also found that half of the patients with
a history of heart disease had LDL cholesterol levels lower than 100
mg/dL, and 17.6 percent of patients had LDL levels below 70 mg/dL, which
are guideline targets for LDL cholesterol in those at fair risk and at
high risk for cardiovascular disease, respectively.
The study also showed that HDL cholesterol, or
"good cholesterol," levels have dropped in patients hospitalized for
heart attack over the past few years, possibly due to increasing rates
of obesity, insulin resistance and diabetes.
Researchers found that 54.6 percent of patients had
HDL levels below 40 mg/dL. Developing more effective treatments to boost
HDL levels may help reduce the number of patients hospitalized for heart
attacks, according to the authors.
"We found that less than 2 percent of heart attack
patients had both ideal LDL and HDL cholesterol levels, so there is room
for improvement," said Fonarow.
Fonarow said that only 59 percent of patients in
the database had their lipid levels checked upon admission, which should
be increased, since these early measurements can often help guide
treatment decisions.
He also noted that only 21 percent of patients in
the study were taking lipid-lowering medications before admission,
despite almost half having a prior history of cardiovascular events,
which would prompt treatment.
Background Information
The national cholesterol guidelines are set by the
National Cholesterol Education Program, part of the National Heart, Lung
and Blood Institute of the National Institutes of Health.
The study was sponsored by the Get with the
Guidelines program, which is supported by the American Heart Association
in part through an unrestricted education grant from the Merck Schering
Plough Partnership.
Fonarow has conducted research for GlaxoSmithKline
and Pfizer and serves a consultant and has received honorarium from
Abbott, AstraZeneca, GlaxoSmithKline, Merck, Pfizer and Schering Plough
companies. He is also chair of the Get with the Guidelines steering
committee.
Other authors include: Dr. Amit Sachdeva,
Department of Medicine, David Geffen School of Medicine at UCLA, Los
Angeles, CA; Dr. Christopher P. Cannon, Brigham and Women's Hospital &
Harvard Medical School, Boston, MA; Dr. Prakash C. Deedwania, Department
of Cardiology, VA Medical Center/UCSF School of Medicine, San Francisco,
CA; Dr. Kenneth A. LaBresh, Masspro, Waltham, MA; Dr. Sidney C. Smith,
Jr., University of North Carolina School of Medicine, Chapel Hill, NC;
David Dai, MS and Dr. Adrian Hernandez, Duke Clinical Research
Institute, Durham, NC.
