December 18, 2013
News Review From Harvard Medical School -- New Guidelines Shift Blood Pressure Goals
Long-awaited new guidelines allow slightly higher blood pressure for people over 60 and those with some conditions. These are the first new guidelines since 2003. An expert panel wrote them. Other experts reviewed them. For the first time, they are based as much as possible on randomized controlled trials. Such studies are considered the highest standard of evidence. They assign similar people to different treatments or a placebo (fake). If these studies were lacking, the guidelines relied on expert opinion. The new guidelines recommend treating blood pressure in people ages 60 and older if it is above 150/90. For people ages 30 through 59, the goal remains less than 140/90. For this group, only the goal for diastolic pressure (the second number, 90) is based on evidence. The systolic goal (the first number) is based on expert opinion. The goal for people with diabetes or non-diabetic kidney disease is also less than 140/90. The previous goal was less than 130/80. But the panel said there was not enough evidence to support the lower goal. The guidelines also recommend types of medicines for different groups of patients. The Journal of the American Medical Association published the guidelines. The Associated Press wrote about it December 18.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
About 78 million American adults have high blood pressure (hypertension). It affects more than two-thirds of people over age 60. It is the most common factor that increases the risk of heart disease and stroke. And yet only 50% of people with high blood pressure have it well controlled.
Until now, well controlled blood pressure for people without diabetes or kidney disease meant having most readings under 140/90. That's been the goal defined by the previous guidelines for the management of high blood pressure. Those guidelines are known as JNC7 (short for the Seventh Joint National Committee on Hypertension).
In today's Journal of the American Medical Association, we find the long-awaited new guidelines, called JNC8.
The previous guidelines were created using a combination of different types of studies and expert opinions. The panel that wrote JNC8 set out to use only randomized controlled trials. They wanted to make sure their advice was evidence-based.
In medical research, randomized clinical trials are considered the gold standard for answering clinical questions. These studies randomly assign similar patients to receive different treatments or a fake treatment (placebo). Usually, no one knows who is in which group until after results are analyzed. This design helps to make results unbiased and reliable.
However, despite the best efforts of the authors of the new guidelines, only some of their advice is supported by evidence from this type of study. Most of it still had to be based on expert opinions. The randomized controlled trials needed to answer many of the important questions about treating high blood pressure had not been done, or their quality was not high enough.
The authors should be applauded for what they have accomplished. This was an incredibly difficult task. They openly acknowledge which advice is based on expert opinion and not evidence from clinical trials. And they have agreed to share all of the comments and communications that occurred before publication. These came from experts both inside and outside the panel.
What Changes Can I Make Now?
Know your blood pressure. Take advantage of any chance you have to get your blood pressure checked. For example, many pharmacies have blood pressure devices that you can use for free.
For now, still consider a reading of 140/90 or greater to be higher than ideal. If your blood pressure is above this level, you need to act. This might mean just getting another couple of readings over a few weeks. Or, if it is very high, call your doctor's office to arrange an appointment soon.
Even if your blood pressure is within the normal range, have it checked at least yearly. Better yet, take advantage of free blood pressure checks two to three times per year.
The guidelines provide some solid advice about the best choices to make if you do need medicine to lower your blood pressure:
- If you are black and have normal kidney function, start with a low-dose, thiazide-type diuretic (such as chlorthalidone or hydrochlorothiazide) or a calcium channel blocker. Another option would be a pill that contains very low doses of both drug types.
- If you are not black and have normal kidney function, start with a low dose of one of these drug types:
- Angiotension-converting enzyme (ACE) inhibitor
- Angiotensin receptor blocker (ARB)
- Thiazide-type diuretic (such as chlorthalidone or hydrochlorothiazide)
- Calcium channel blocker
- Or a pill that contains very low doses of two different drugs
- If you have impaired kidney function, consider starting with a low dose of an angiotension converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB). But never use both together. These types of drugs help protect the kidneys from further damage.
Everyone with high blood pressure should lose weight if necessary. Cut back on salt, eat a diet loaded with vegetables and keep physically active.
No matter what the guidelines say, your blood pressure treatment and goals should be tailored to you personally. For example, a very old and frail person is more likely to feel better and have less fall risk with fewer medicines and a blood pressure higher than 150 or even 160.
What Can I Expect Looking to the Future?
Not everyone will be happy with the new guidelines. For example, they suggest that a systolic blood pressure (the top number) for most people age 60 and older is acceptable at less than 150. Many experts will say that this goal is too high for people in this age group. It may lead to an increase in the number of heart problems and strokes.
There are studies suggesting that may be true. But the evidence is not strong enough to say for certain that a blood pressure under 140 leads to better outcomes. We might find in future studies that using a goal of less than 150 for most people over age 60 is fine.