By
Harlan M. Krumholz, M.D.*
 |
|
New guidelines
suggest that people over age 60 can have a higher blood pressure than
previously recommended before starting treatment to lower it. Toby
Talbot/Associated Press
|
The
long-awaited new
hypertension guidelines will change how we approach patients with high
blood pressure. Here are three things you should know about them.
First,
the guidelines raise the systolic blood pressure (the top number of the blood
pressure reading) threshold for drug treatment from 140 to 150 for people 60
and older.
You
may be familiar with the idea that hypertension should be treated when your
blood pressure is higher than 140/90 mm Hg. Now, based on studies, the experts
suggest starting drug therapy only when the reading is 150/90 or higher. In
fact, the authors, some of the most prominent experts in the diagnosis and
treatment of high blood pressure, said that the goal of drug treatment is to
lower the blood pressure below 150/90.
This
recommendation immediately puts many people who had drug treatment started
because of mild elevations in systolic hypertension in an overtreatment
category. Many people currently on drug treatment would not have been
recommended for treatment under these new guidelines, including those who had
high-normal values and were being treated for so-called pre-hypertension, a
condition never officially sanctioned for treatment.
Second,
there is insufficient medical evidence to support a systolic blood pressure
threshold for the drug treatment of people younger than 60.
Let
me repeat that. After all these years of studying people with high blood
pressure, the panel concluded that there was insufficient evidence to support a
recommendation for this large segment of the population.
Now
that did not stop the authors from expressing an opinion that we ought to stay
with the current threshold of a blood pressure lower than 140 for those younger
than 60. They argued that there was no reason to change what we have been doing
– even though it has been based on opinion and not evidence. My take here is
that the evidence for this threshold is weaker than most people might believe –
and decisions about treatment need to acknowledge this uncertainty and defer to
the preferences of patients.
The
authors of the guidelines similarly also stated that we lack evidence for the
right target for patients with kidney disease and diabetes. Given the lack of
evidence, the authors settled on a recommendation of a goal of less than 140/90
for patients for people with kidney disease and also those with diabetes. This
is a change for many people because many doctors have been seeking a systolic
blood pressure goal of less than 130, but the authors noted that such a
recommendation is not supported by any clinical trial.
Meanwhile,
they do indicate that the diastolic blood pressure (the bottom number) should
be less than 90, and for people age 30 and older there is evidence to support
that recommendation.
Third,
the guidelines recognize that the modification of a risk factor – in this case
hypertension, which is a risk factor for heart attacks and strokes and
premature death – by drug therapy does not necessarily mean that you have
reduced someone’s risk for these adverse health events.
What
we discovered in studies was that treating mild elevations of blood pressure
with drugs does not reliably improve patients’ health. Although there is no
question that drug treatment of very high blood pressure levels is beneficial,
we now have several studies that failed to reduce risk by lowering blood
pressure from mildly elevated to lower levels. Several studies sought to reduce
risk by lowering blood pressure from mildly elevated to lower levels – and the
surprising finding was that there was no benefit.
What
this means is that drugs have many effects, and their effect on a single risk
factor does not capture all they are doing and cannot convey their net effect
on someone’s health. We have so many examples of trying to change risk factors
with drugs and doing no good – or even harm – even as we make a single risk
factor look better.
The
authors of the guideline were influenced by these studies and did not default
to the idea that more treatment is better. They reflected on what we know from
studies that tested specific treatment strategies, which led them to be more
conservative in their recommendations than previous guidelines.
Additionally,
there are other important aspects of these guidelines. While they focus on drug
treatment, they do emphasize the importance of a healthy diet, weight control
and regular exercise. They make separate recommendations for black and white
patients. They steer people away from beta-blockers for the treatment of high
blood pressure. They steer black patients away from ACE inhibitors or
angiotensin receptor blockers. They steer all people toward thiazide-type
diuretics and calcium channel blockers.
In
summary, this is a large paradigm change. The authors state that they did not
intend to redefine what constitutes high blood pressure, but in effect they
have now set it at 150/90 for the purpose of drug treatment of the general
population. They have illuminated the weakness of our current body of evidence
and made sensible recommendations given what we know.
The
new guidelines are a reason for people being treated for high blood pressure to
start 2014 with a discussion with their doctor, particularly if they started
drug treatment for mildly elevated blood pressure.
As always, all decisions
about your treatment should reflect your own preferences about whether the
benefits are worth the risks. What these guidelines reveal is that many
decisions about blood pressure treatment are being made with less evidence than
we need. This is a call to action for studies that can equip patients facing
decisions about treatment with the information they need.
*Harlan
Krumholz is a cardiologist and the Harold H. Hines Jr. Professor of Medicine,
director of the Yale-New Haven Hospital Center for Outcomes Research and
Evaluation and director of the Robert Wood Johnson Clinical Scholars Program at
Yale University School of Medicine.
Source: http://well.blogs.nytimes.com
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