Lower cholesterol, lower blood pressure now expected
Brad Evenson
National Post
Thursday, October 30, 2003
To all Canadians who plan to get a medical exam soon: Brace yourselves for
bad news.
That beer belly is no longer a source of humour. Your borderline blood
pressure has crossed the border. And those cholesterol levels that last week
seemed normal, are now the dark precursors of a heart attack.
Guidelines for what is "normal" cardiovascular health have fallen. The new
normal is lower, lower, lower.
As a result, millions of Canadians with no outward signs of heart disease
can soon expect to be prescribed a shelf-load of pills, including statins,
diuretics and ACE inhibitors, to safeguard their hearts.
"In the past we looked at a lot of patients as kind of being in the grey
zone and decided, 'Well, maybe we'll try diet for another year,' " says Dr.
Ruth McPherson, director of the lipid clinic at the University of Ottawa
Heart Institute. "Now we're being a little more categorical that these
people definitely will benefit from treatment."
This week, the Canadian Medical Association Journal published a summary of
new guidelines for blood fats. Among the most stringent in the world, they
shift focus from so-called bad (LDL) cholesterol toward the lack of good
(HDL) cholesterol levels. They also cast a suspicious eye on big waistlines
and insulin levels.
The shift follows changes in May to blood pressure guidelines, which
replaced the category "high normal" with the worrisome-sounding label
"pre-hypertensive."
"Definitely more people are now candidates for [drug] treatment," says Dr.
McPherson, part of the working group that drafted the new cholesterol
guidelines.
"And some people are concerned about that. But the truth is that the safety
of these medications is well established."
The upshot is that people who three years ago could be told they were
reasonably healthy will now be informed they are ticking cardiac time bombs.
Researchers have been fighting for years over the best ways to predict and
ward off heart disease.
In recent years, such studies as the MIRACL trial and the Heart Protection
Study have shown if you have a family history of heart disease, are
overweight, diabetic or hypertensive, then treatment with lipid-lowering
statins such as Lipitor or Zocor can save your life. "Even if you have a
rock-bottom cholesterol level, if you have heart disease, going on statins
definitely decreases your risk of having heart attacks and dying of heart
disease," says Dr. McPherson. "That risk is decreased, in different studies,
anywhere from 25% to 50%."
Now that they know it's possible to prevent cardiovascular disease, doctors
are now inclined to be stickier about details.
For example, research shows artery damage can start at blood pressure levels
as low as 115/75 and doubles for each 20/10 millimetres of mercury.
Previously, such levels were considered satisfactory.
At least four million Canadians have hypertension, sometimes known as the
silent killer. Up to 30% of victims do not realize they have it. Controlling
blood pressure can reduce the incidence of stroke by 40%, reduce heart
attacks by 25% and lower the rate of heart failure by 50%.
So hypertension guidelines have fallen.
Previously, systolic pressure of 130 to 139 and diastolic pressure of 85 to
89 were deemed "high normal." (Systolic is the pressure on blood vessels
when the heart muscle is contracting, and diastolic is the pressure when the
heart is pausing between beats.) Now this pressure is called
pre-hypertensive, a name meant to evoke concern. Patients in this category
may be told to lose weight, quit smoking and reduce salt consumption, or in
some cases may be prescribed such drugs as diuretics -- "water pills" -- and
ACE inhibitors.
Many doctors find these new guidelines a headache.
"The goal is to keep blood pressure below 140/90," said a Vancouver family
physician who asked not to be named.
"But it's incredibly difficult. You need to use huge doses of drugs to get
there. Patients have to be really committed. And let's face it, [high] blood
pressure has no symptoms. So a lot of patients don't take it seriously."
The new cholesterol guidelines may be equally troublesome.
They recommend doctors use a ratio of total cholesterol to HDL cholesterol,
an index shown to be a very good predictor of heart disease. The goal for
most Canadians is to have a ratio of lower than 5.0. But even in people at
low risk for heart disease, a ratio of 6 or higher would prompt a doctor to
prescribe drugs.
That has raised serious concerns.
Last month, a controversy erupted when researchers from the University of
British Columbia questioned the wisdom of giving statins to patients with
high cholesterol but no evidence of hardened arteries. "The best estimate of
the treatment benefit is a 1.4% reduction in heart attacks and strokes," Jim
Wright, a UBC professor of pharmacology, wrote in a letter to the National
Post.
Not only is this potential benefit small, Dr. Wright said he is not
confident that long-term treatment with statin drugs is as safe as many
researchers believe. An editorial this week in the British medical journal
The Lancet raised similar concerns, saying not enough research had been done
to support the safety and efficacy claims made by AstraZeneca for Crestor,
its statin drug.
Many researchers dispute Dr. Wright's concerns, but concede the potential
benefit of treating patients at low risk for heart disease is probably quite
small.
Others say drug therapy is not the only answer.
For example, earlier this year, University of Toronto researchers showed
that eating an "ape" diet, similar to what humans consumed five million
years ago, cuts down cholesterol as effectively as pharmaceutical drugs.
The nutrition study, published in the Journal of the American Medical
Association, said a diet rich in nuts, fibrous grains and vegetable
proteins -- what our primate cousins eat every day -- can prevent heart
disease.
Finally, the new normal guidelines put a clear definition on an increasingly
common woe known as the metabolic syndrome. When three risk factors occur in
one patient, the danger of heart disease skyrockets. The new guidelines say
if a patient has a waist circumference of greater than 102 centimetres (88
cm for women), high triglycerides, fasting glucose of 6.2 to 7.0, low HDL
cholesterol and blood pressure higher than 130/85, then the patient is at
substantial risk of heart disease.
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