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Expert Q & A

The Worldwide Challenge of Blood Pressure Control

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Dr. Aram Chobanian is a professor of medicine and pharmacology at the Boston University School of Medicine. He chairs the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure, a government-sponsored board that makes recommendations for controlling hypertension.

Jodi Hilton for the New York Times

Dr. Aram Chobanian

Q: Nearly one in three Americans has hypertension, and the rate appears to be rising. Is there something about living in the United States that makes us prone to high blood pressure?

A: It’s high not just in the United States but all over the world. The total hypertensive population is in order of one billion individuals. The percentage in this country with high blood pressure is pretty similar to other areas in the world.

Q: What is behind the rising rates of high blood pressure?

A: A lot of it is environmental. With the epidemic of obesity that’s going on in this country as well as other parts of the world, blood pressure levels are going up in tandem.

The aging population is another important factor. Older individuals get more hypertension primarily because of the stiffening of their primary arteries. If you live long enough, almost all individuals will have blood pressure that is considered to be abnormally high.

Q: Can we eliminate hypertension if we followed a healthier lifestyle?

A: I don’t think we can wipe out hypertension, even if we did everything right. About 40 percent of those who are obese have high blood pressure - but not all of them. And not all lean people have normal blood pressure.

We know that something on the order of 60 to 70 percent of those with hypertension has a family history of the disease. Now that doesn’t necessarily mean that it’s genetic, because families do a lot of things together - their diet, obesity, salt intake. It’s hard to determine because the genetic and environmental factors are so closely related. But I think we could reduce the prevalence of hypertension substantially with lifestyle changes.

Q: What should be our ideal blood pressure?

A: What the Joint National Committee recommended as normal is 120 [mmHg] over 80 [mmHg]. But if you go higher than that, in a range between 120 to 140 over 80 to 90, there’s a new category that’s been defined as prehypertension. In terms of intervention or therapy, it highlights individuals who may benefit from lifestyle changes, or maintenance of a healthy lifestyle.

Q: Some doctors question whether prehypertension is really something to worry about. What caused the committee to add this classification to its treatment recommendations?

A: It took into consideration new information regarding risks. If you start at a systolic blood pressure as low as 115 and diastolic as low as 75 and go up from that point, there’s a progressive risk for heart and kidney disease. And for every 20 over 10 millimeter rise in blood pressure, we know there’s a doubling of risk for heart disease and stroke.

So 115 over 75 is a very normal blood pressure. But if you go to 135 over 85, which by some criteria would still be normal blood pressure, that person would be at double the risk for heart attack or stroke.

Q: Still, some critics have charged that this distinction is a way for pharmaceutical companies to sell more drugs. How do you respond?

A: That was not a consideration, because the recommendations in the report were very strong that these individuals should be treated with healthier lifestyles. The only ones in the group who should be considered for medicine are the ones with kidney disease or diabetes, and very recently this was broadened to people with heart disease. The idea that this is to help the pharmaceutical industry is an erroneous one. These are guides, they are not absolutes by any means.

Q: How long do people generally have high blood pressure before they suffer a heart attack or stroke?

A: It depends on a lot of factors, including other risk factors. Hypertension does not live in a vacuum. The individual who has hypertension may or may not have high cholesterol, or diabetes, or be overweight.

So it varies. On average, it may take 20 years before someone has a clinical manifestation of the disease, meaning chest pains, heart attack, heart failure, circulatory problems.

Q: Are there any symptoms to look out for?

A: There are very few symptoms until a person has a complication. But during that period of time the damage is going on.

Q: Should you make regular doctor appointments to have your blood pressure checked?

A: Most people have contact with a health care provider once or twice a year, whether it’s going to a doctor for a physical or going to an emergency room for a sore throat. If blood pressure was taken during those times, that would be more than adequate to monitor for any changes. The contacts are there, so I don’t think everyone has to make a special visit for blood pressure.

Q: People with hypertension have more than 60 medications to choose from. How do you go about picking the right drug?

A: It doesn’t make a huge amount of difference which drug you use. There are very minor differences, depending on if you have high cholesterol or diabetes. In general, we have five good classes of drugs that are used. The physician can to some extent tailor treatments to patients.

One thing we know is that we have enough options available so side effects that are significant should not be tolerated. If one drug is not well accepted by the patient, you should go to a different one from a different class. There are very few people who can’t have their blood pressure controlled with medicines.

Q: The Joint National Committee guidelines say that doctors should first prescribe diuretics, which are the oldest treatments out there. Why?

A: Diuretics certainly do as well as any other drug class, and they’re cheap. An important point is that almost two-thirds of hypertensive patients need more than one drug to control their blood pressure. Diuretics are one of the two drugs you would use because they work so well with other agents.

Q: Despite the guidelines, many doctors still prescribe the newer, more expensive drugs first. Do you think pharmaceutical companies have an impact on which medications are used?

A: I think the pharmaceutical industry does have a big impact on prescribing practices, but you have to balance off the positives and the negatives. The physician has to make the decision on what to use, and that decision is facilitated by the fact that we have so many good drugs out there. I can’t argue if a physician wants to use another drug as initial therapy and if blood pressure doesn’t respond, then they can add a diuretic.

Q: The guidelines also state that restricting salt, getting regular exercise and following a proper diet are “indispensible” for treating hypertension? How big of a difference can lifestyle measures make once you have the disease?

A: If you can get a person to lose weight, which usually means a combination of diet and exercise, this will have a substantial effect on blood pressure. The problem is that only a relatively small percentage of patients are able to lose weight and keep it off.

But there are other ways as well. There are diets now that are emphasizing high intakes of fruits and vegetables, low-saturated-fat foods and a lot of grains. These have had a substantial effect on blood pressure to at least the amount that you see when you use one blood pressure lowering drug.

The DASH [Dietary Approaches to Stop Hypertension] diet has been very useful in the treatment of hypertension. And the nice thing about the diet, exercise and weight reduction is that it also helps reduce the risk of diabetes and lowers cholesterol. So you get a much bigger bang for your buck.

Q: What if we were to simply cut back on salt?

A: In very-low-salt-consuming societies, it’s very clear that the prevalence of hypertension is quite low. On the other hand, when you look at the average American population, there’s a wide range of sensitivity to salt.

It would appear as if 40 to 50 percent of those with hypertension are sensitive to salt to a degree where if you reduce salt intake you get a demonstrable decrease in blood pressure. But within the limits of the average population you may not see much change with modest reductions because our salt intake is so high.

Q: How do you get people to follow a healthy lifestyle to treat, or ideally prevent, hypertension?

A: It’s difficult. You have to have motivated people. There are individuals who have so many other priorities in their life that the diet becomes a very low priority. I think better education of young people, that’s the real long-term way of doing it.

But it’s a problem that permeates so many different aspects of life -- food advertising, fast foods and the store chains. It’s not something that one group or one city can do. It has to be a national effort.

Publish date: 01/23/2008

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