Another
New Disease “PreHypertension”
U.S.
Lowers 'Normal' Levels for Blood Pressure Readings. The
risk of heart disease and stroke starts to rise at readings
as low as 115/75, and doubles for each increase of 20/10
millimeters of mercury.
Millions
of people have been told they have PreDiabetes will now
be told they also have a condition called PreHypertension
and they both threaten their health according to the new
guidelines issued last week by government health experts.
The new category PreHypertension includes 45 million Americans
whose blood pressure is 120 to 139 millimeters of mercury
systolic (the top number) or 80 to 90 diastolic (bottom
number). People with readings in this range do not have
high blood pressure yet and do not need to take medication.
Since
people that have diabetes have a greater risk for CVD, then
the new guidelines would also have to apply to those with
diabetes and the previous guidelines of 135/80 for those
with diabetes will no longer apply and the new guidelines
will apply for anyone whose BP is above 115/75, but are
those readings realistic to obtain?
But
the new guidelines advise doctors that such people are likely
to develop high blood pressure, and should be urged to try
to lower their pressure by losing excess weight, exercising
more, quitting smoking, cutting back on salt, having no
more than one or two alcoholic drinks a day and eating more
fruits, vegetables and low-fat dairy products.
The
guidelines and a report were issued by the National High
Blood Pressure Education Program, part of the National Heart,
Lung and Blood Institute. They were posted yesterday on
the Web site of the Journal of the American Medical Association,
at www.jama.com, and will be published in the journal's
May 21 issue.
It
has long been known that elevated blood pressure is a serious
health threat, but this report represents the first time
that the government's blood pressure panel has flagged relatively
low readings as a harbinger of disease.
A statement
issued by the institute said the new recommendations were
based on studies showing that artery damage and an increased
risk of cardiovascular disease can begin even at blood pressure
levels that until recently were thought to be normal. The
risk of heart disease and stroke starts to rise at readings
as low as 115/75, and doubles for each increase of 20/10
millimeters of mercury.
The
report urges doctors and patients to take high blood pressure
more seriously and treat it more aggressively, often with
more than one drug. High blood pressure greatly increases
the risk of heart disease, stroke and kidney failure. Heart
disease, which kills more than 700,000 Americans a year,
is the nation's leading cause of death.
"The
prehypertension area is important," Dr. Edward J. Roccella,
coordinator of the program, said. "We want people to
act long before the disease is established, to prevent the
progressive blood pressure rise."
In
addition to weight loss and diet changes, he said, the program
was recommending 30 minutes of exercise most days, which
could be broken into two 15-minute walks.
"If
you don't have time for physical activity, you will have
time for illness," Dr. Roccella said. "Illness
doesn't make an appointment."
Blood
pressure tends to increase steadily with age, and the new
report says that even people whose readings are normal at
the age of 55 have a 90 percent chance of eventually developing
high blood pressure, although changes in diet and exercise
can ward it off.
The
guidelines define normal blood pressure as a reading below
120/80 millimeters of mercury. High blood pressure is defined
as any reading above 140 millimeters of mercury systolic
(top number) or above 90 diastolic (bottom number). The
top number is the pressure in the arteries when the heart
is contracting, and the bottom number is the pressure when
the heart is at rest between beats.
Information
is available at www.nhlbi.nih.gov/guidelines
/hypertension.
The
last report from the same group, in 1997, allowed slightly
higher pressures to be classified as normal, and gave the
label high normal to systolic levels of 130 to 139 and diastolic
levels of 85 to 89. The new guidelines eliminate the high-normal
category.
Fifty million Americans, or one in four adults, have high
blood pressure, also called hypertension, and only a third
of them have it under control. A billion people worldwide
are affected. In most cases, the cause is not known.
Hypertension
has no symptoms, and 30 percent of those who have it are
not aware of it. The pressure does its damage by injuring
the arteries and causing them to stiffen, which increases
the pressure more.
The
new report suggests that better control of blood pressure
could drastically reduce the number of deaths from heart
attack, heart failure, stroke and kidney disease. Lowering
high blood pressure may also reduce the progression of dementia
and cognitive impairment, which are more common in people
with hypertension.
The
report also states that controlling hypertension has been
associated with a 35 to 40 percent average reduction in
the incidence of stroke, a 20 to 25 percent reduction in
heart attacks and more than a 50 percent reduction in heart
failure. The report also estimates that in patients with
other cardiovascular risk factors, a sustained 12-point
reduction in systolic blood pressure over 10 years will
prevent one death for every 10 patients treated.
Although
for many years doctors believed, and advised patients, that
the more important number in a blood pressure reading was
the bottom one, or diastolic pressure, in the last decade
or so studies have shown that the top number is at least
as important, especially in older people, in whom it tends
to rise. Drugs to lower blood pressure usually work for
both readings, Dr. Roccella said.
When
blood pressure is high enough to require medication, the
goal for most people is to get it below 140/90, although
those with diabetes or kidney disease are urged to aim for
130/80. Even though normal is considered 120/80, that is
simply not a realistic goal for many patients, Dr. Roccella
said.
Several
classes of drugs are used to treat hypertension, including
diuretics, commonly called water pills, as well as beta
blockers, calcium channel blockers and ACE inhibitors. Some
people can get results with one drug, but those with higher
levels often need more than one, the report said. Many of
the medicines have been combined so that patients can take
two drugs in a single pill.
Many
of the drugs can have side effects like lightheadedness,
coughing and sexual problems, but not all patients suffer
from them. Those who do can often switch to a different
type of drug that will lower blood pressure without causing
problems, said Dr. Aram Chobanian, dean of the Boston University
Medical School and chairman of the committee that produced
the guidelines.
"We wouldn't say, `Stay on one line of drugs if you're
having side effects,' " Dr. Chobanian said.
The
report notes that for unknown reasons African-Americans
have better results with diuretics and calcium blockers
than with beta blockers, ACE inhibitors or angiotensin receptor
blockers, and that blacks are also more likely than whites
to suffer side effects from ACE inhibitors.
The
report says that many people benefit from diuretics, alone
or in combination, but adds that they are underused and
should probably be prescribed more often.