News Review From Harvard Medical School -- Weight May Affect Blood Pressure Treatment
Whether you're overweight or not may affect how well a blood pressure drug works for you, a study suggests. Researchers looked at data from a study of more than 11,000 people with high blood pressure. People were randomly divided into 2 groups. Both groups took Lotensin (benazepril). This is a type of blood pressure drug known as an ACE inhibitor. One group also took hydrochlorothiazide, a diuretic. The other group took Norvasc (amlodipine) as their second drug. This drug is known as a calcium channel blocker. Among those taking the diuretic, people whose weight was normal had the worst results. They were 68% more likely to die or have a heart attack or stroke than obese people taking a diuretic. Taking the calcium channel blocker worked better for people of normal weight. They had a 43% lower rate of death, stroke and heart attack than those who took the diuretic. For people who were overweight, the risk reduction was 24% with the calcium channel blocker. For people who were obese, both drug combinations worked equally well. The journal Lancet published the study online. HealthDay News wrote about it December 6.
By Robert H. Shmerling, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
High blood pressure, or hypertension, has long been called "The Silent Killer." That's because it rarely causes symptoms and yet increases the risk of diseases that can be deadly, such as heart attack and stroke.
Most people need medicine to bring their blood pressure down. But which medicine is best? The most common choices for a first treatment are:
- ACE inhibitors, such as benazepril or lisinopril
- Beta-blockers, such as atenolol or metoprolol
- Calcium channel blockers, such as amlodipine or nifedipine
- Diuretics, such as hydrochlorothiazide
Most studies have found these treatments to be similar overall in how well they lower blood pressure. Studies suggest that black patients improve more with a thiazide diuretic or a calcium channel blocker than with other drugs. But for most people it's impossible to predict which drug will work best. That's why the treatment of high blood pressure is often a process of trial and error.
Is there a better way? Perhaps genetic testing will someday allow doctors to pick a drug that is likely to work well and unlikely to cause side effects. Or perhaps a future test will identify a chemical or hormone in blood that could guide the choice of treatment.
Or there may be a much simpler way: Just check the person's height and weight. That's a conclusion suggested by a new study in the journal Lancet.
Researchers looked at data from a trial of different treatments for more than 11,000 people with high blood pressure. They studied the impact of body mass index (BMI) on how well treatments worked. BMI is a measure of weight that adjusts for height. A normal BMI is 19 to 25. Someone is overweight with a BMI of 25 to 30 and obese if it's over 30.
In this study, both groups received the ACE inhibitor benazepril. One group also took the diuretic hydrochlorothiazide. For the other group, the second drug was amlodipine, a calcium channel blocker.
Here's what the study found:
- Those with a normal BMI did not fare as well with the treatment that included a diuretic.
- The treatment that included a calcium channel blocker worked equally well for people of different BMIs.
- Among people who had a normal BMI or were overweight, those treated with a calcium channel blocker had a lower rate of heart and artery problems than those taking the diuretic. The reduction in events such as heart attack or stroke was 43% for those with a normal BMI and 24% for those who were overweight.
- Both drug combinations worked equally well for those who were obese.
The cause of most high blood pressure is unknown. But these findings suggest that the cause may be different in people who have a normal BMI than in people who are overweight or obese. The treatment would differ as well.
Still, the importance of this new study is not entirely clear. It did not study single-drug treatment. That's how treatment is usually started. Other patient factors also may affect the choice of treatment. These include race, kidney function and heart function. Other researchers need to confirm these new results before doctors begin choosing treatment based on BMI.
What Changes Can I Make Now?
You can make changes now that could prevent high blood pressure in the future. Here are some steps you can take:
- Lose excess weight.
- Change your diet. Eat less salt (as in the DASH diet) and drink only moderate amounts of alcohol. Choose a high-fiber diet and eat more fruits and vegetables.
- Exercise regularly.
These same changes may be helpful if you already have high blood pressure.
The only way to know if you have high blood pressure is to have your blood pressure checked. Make this a routine part of your medical care. You don't even have to wait for a doctor's visit. Many drug stores and work places offer blood pressure tests.
If you have already been diagnosed with high blood pressure, see your doctor regularly. Your doctor may recommend other diet and lifestyle changes, monitor your medicines for side effects, and help you decide whether a change in treatment is needed. As noted in this latest research, your BMI may help your doctor choose a medicine.
Finally, it's important to pay attention to other factors that increase the risk of heart and artery disease. They include:
- High cholesterol
- Family history
You can't change your family history. But these other risk factors can be changed or treated. Review your options with your doctor.
What Can I Expect Looking to the Future?
In the future, medical practice is likely will rely on "personalized medicine." Treatment choices will be based on features unique to each person. For high blood pressure, your doctor may recommend a drug based on your BMI, genetic makeup, or several factors.
Personalized medicine is expected to revolutionize the practice of medicine. And that means the treatment of high blood pressure is likely to be quite different from how it's done now.