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Blood Pressure

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News on blood pressure drugs

Behind the scenes at your doctor’s office debate continues about which drug should be the first line of treatment for high blood pressure. Diuretics (also known as water pills) have been around for decades, but the makers of newer, more specialized — and more costly — drugs have been wooing physicians and their patients. The question isn’t whether these drugs work effectively to lower blood pressure; they do. But evidence indicating which is best at reducing heart disease and other cardiovascular events has been missing — until now.

The ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) study was designed to compare a diuretic to three other commonly prescribed classes of antihypertensive drugs — calcium channel blockers (CCBs), alpha-adrenergic blockers, and angiotensin-converting enzyme (ACE) inhibitors. The study involved 42,000 patients over the age of 55 with hypertension and one other risk factor for heart disease, such as previous heart attack or stroke. Each of the patients was randomly assigned to receive one of the study drugs for four to eight years. Researchers monitored the patients’ blood pressures and recorded evidence of heart disease and cardiovascular events.

Part of the study was halted early when evidence showed patients taking the alpha-adrenergic blocker had higher rates of cardiovascular disease and heart failure than patients taking the diuretic.

The primary results of the comparison of the ACE inhibitor lisinopril and the CCB amlodipine to the diuretic chlorthalidone were striking. The occurrence of death from heart disease was the same across each of the groups, and the rate of nonfatal heart attack was also similar. However, a slightly higher percentage of patients taking the diuretic chlorthalidone achieved better blood pressure control. Chlorthalidone was also better at preventing heart failure than amlodipine, the CCB. Patients taking the ACE inhibitor lisinopril had a higher risk of stroke, angina, and heart failure. In particular, black participants who took lisinopril had a 40% higher risk of stroke than black participants who took the diuretic.

The findings of the ALLHAT study indicate that when it comes to drugs for high blood pressure, newer and more costly does not mean better. In fact, diuretics should be the first line of treatment for many people with high blood pressure. Not only are they better at controlling high blood pressure while preventing major cardiovascular events, diuretics also cost less than the other drugs. A one-year supply of Chlorthalidone costs about $96, while the CCB amlodipine would set you back $480. Lisinopril costs $384 a year for the brand name drug (either Zestril or Prinovil), and $240 for the generic.

What should you do with these study results? If you’re just starting drug treatment for high blood pressure, you might want to try a diuretic first. If you, like most people, need a combination of drugs to keep your blood pressure in check, one should probably be a diuretic. If you’re already taking a different kind of medicine and it is working well for you, there’s no need to switch. However, if you want to cut down your drug bills, you might want to talk to your doctor about a diuretic.

(Journal of the American Medical Association, December 18, 2002)

February 2003 Update

Killer snow

Every winter, about 1,200 Americans die from a heart attack or some other cardiac event during or after a big snowstorm, and shoveling is often the precipitating event.

Why is shoveling so hazardous?

Shoveling uses your shoulders and arms, and upper body exercise tends to put strain on the heart because those muscles aren’t well conditioned.
Working in an upright position adds to the arduousness because blood pools in the legs and feet, so to maintain blood pressure, your heart must work harder.
Much of snow shoveling is isometric exercise: your muscles are working, but there's little actual movement until you finally heave a shovelful up on the bank. During isometric exercise of any type, your heart rate goes up, and your blood vessels constrict, presumably to send more blood to the straining muscles. As a result, your blood pressure goes up.
Without knowing it, shovelers sometimes perform a version of the Valsalva maneuver, bearing down as they would during a bowel movement while holding their breath. Waiting to exhale while straining like that can lead to abrupt changes in your heartbeat and blood pressure.
First thing in the morning, the time when many people dig out from a storm, stress hormone levels tend to be higher, platelets in the blood “stickier,” and heart attacks more likely.
Shoveling involves exposure to the cold, another cardiac stressor.
People who are out of shape often shovel, making the sudden intense exercise even harder on the heart.
Most people don’t warm up before they shovel or cool down afterward.

If you have a heart condition, you shouldn’t shovel under any circumstances. People older than 50 should also try to avoid it. Contact your local council on aging to see if they provide a list of teens in your neighborhood who you can hire to do the job for you. Or buy a snow blower. If you must shovel, take it easy. Rest often. Dress warmly and stay well hydrated. Wherever possible, push the snow rather than lift it. Clear only the snow that blocks your path into the house, the rest will melt on its own. And of course, listen to your body. Head home if you experience potential signs of heart trouble, including chest pain, palpitations, undue shortness of breath, fatigue, lightheadedness, or nausea. Also stop if your fingers or toes get numb or hurt — you could have frostbite.

January 2003 Update

Blood pressure screening

High blood pressure may be the most common chronic condition plaguing adults. Physicians need to know the best method for screening patients to identify and treat those patients with hypertension.

According to previous studies, ambulatory monitoring of blood pressure is the most accurate method. The patient wears a portable device programmed to automatically measure and record blood pressure at frequent intervals. But the device is expensive.

So what is the best alternative? A study published in the August 3, 2002, issue of the British Medical Journal attempts to answer this question. In addition to ambulatory monitoring, blood pressure may be measured by a nurse or doctor, or by the patient. Measurements by a doctor are known to be elevated in some patients because of “white coat hypertension.” In these cases, the anxiety of having one’s blood pressure measured by a doctor causes elevated levels.

One of the purposes of the BMJ study was to determine whether white coat hypertension is seen only in research settings or whether it also turns up in primary care practices. In addition, the study aimed to compare the results of different methods for screening blood pressure. The study involved 200 participants being considered for high blood pressure treatment or who had poorly controlled high blood pressure. Participants had their blood pressure measured multiple times on separate occasions by a doctor, by a nurse, through ambulatory monitoring, and by themselves at home. In general, blood pressure measurements by a doctor were much higher and less accurate compared with the other methods.

The same researchers authored another study in the same issue of the British Medical Journal. They used a questionnaire to determine which method of blood pressure monitoring is most preferred or acceptable to patients. The findings showed patients preferred taking their own blood pressure at home to all the other options. Ambulatory monitoring was less acceptable because it causes discomfort and disturbances to daily life and sleep.

The results of these two studies suggest the most accurate blood pressure readings result from self-screening. If it is not possible, measurement by the patient or a nurse in the clinic will also provide acceptable readings. By screening patients with these methods, patients with white coat hypertension will not be diagnosed with and treated for high blood pressure.

November 2002 Update

Aspirin and heart disease

Should you take aspirin to prevent a heart attack? According to a new study, aspirin helps lower cardiovascular risk, but whether or not you should take it depends on a bevy of factors.

The study, published in the May 9, 2002, issue of the New England Journal of Medicine, analyzes the major trials on the subject. Four out of five of the randomized trials show a reduction in cardiovascular events (especially heart attacks) with aspirin use. (In randomized trials, researchers randomly assign patients to one of the treatments being tested.) But the studies' statistics vary wildly. For example, risk reduction ranged from 4%–44%, depending on the study. All but one trial showed that aspirin use increased the risk of bleeding, most commonly in the stomach.

Two large observational studies also showed that aspirin use decreased coronary events in both people with and without heart disease. (In observational studies, researchers simply monitor subjects' behaviors and health, they do not test a specific treatment on them.) Subjects' ages had an impact in both studies, with aspirin's benefit on the heart kicking in when subjects hit 50 years old in one, 60 years old in the other. Other trials have found that aspirin has the greatest effect on patients with high risk for heart disease.

So what should you do? That depends a lot on your heart disease risk. To calculate your risk go to this downloadable scoring system on the National Institutes of Health Web site.

Then, if you answer yes to any of these questions, talk to your doctor about starting aspirin therapy:

Is your risk for heart disease 1.5% or higher per year?
Is your risk between 0.7% and 1.4% per year? If so, and you answer yes to one or more of the following questions, ask your doctor about treatment:
- Are you in poor physical shape?
- Do you have diabetes or high blood pressure and damage to your organs?
- Do you strongly want to start aspirin therapy?

But if your risk is 0.6% or lower per year, you're probably not a good candidate for aspirin therapy. You should also avoid the therapy if you're allergic to aspirin, prone to bleeding, or suffer from platelet disorders or ulcers. Your own preference is another important factor in making this decision.

Keep in mind that if you have high blood pressure, you'll need to take extra care to control it in order to get the most benefits from aspirin. Also, besides stomach bleeding, aspirin use may cause hemorrhagic stroke.

July 2002 Update

New guidelines for stroke prevention

With more than 700,000 Americans having strokes each year, doctors and patients need to focus on stroke prevention. In light of this, the American Heart Association (AHA) has issued a statement that details how to identify and modify risk factors. Here are the AHA's tips, along with other general guidelines for lowering stroke risk:

Blood pressure. You should get your blood pressure checked at least every two years because many people with high blood pressure don't even know they have it (130–139 mm Hg systolic pressure over 85–89 diastolic pressure is considered high-normal, while anything above 140 over 90 is considered high). If you have high blood pressure, the following lifestyle changes can help lower it:

Eat more fruits and vegetables. Potassium-rich foods like bananas and oranges may be especially good.
Pass on salt. Salt makes the body hold onto water, and the heart has to work harder to pump the extra fluid.
Lose weight. The heavier you are, the harder your heart has to work to pump blood to all parts of your body.
Exercise. Even if you don't need to lose weight, exercise can reduce high blood pressure and may even prevent it.
Limit your alcohol. Having more than two alcoholic drinks a day significantly increases your risk of high blood pressure.
Quit smoking. Smoking increases your risk of heart attack, as well as many other diseases. And if you live with a smoker, make sure he or she quenches his cravings outside. Exposure to secondhand smoke can double your risk of stroke.
Learn to relax. Various kinds of behavioral therapy, like biofeedback, yoga, and tai chi may lower blood pressure.

These lifestyle changes can also help with other causes of stroke, like
atherosclerosis (hardening of the arteries) and high cholesterol. If the changes don't lower your blood pressure, your doctor may prescribe a medication such as a diuretic or beta blocker.

Other conditions. The AHA recommends that patients with diabetes and children with sickle cell disease closely monitor their blood pressure with screenings every six months.

Non-modifiable risk factors. Black, Hispanic, Chinese, and Japanese people are at increased risk for stroke compared to whites. Men and postmenopausal women are also at higher risks than others. If one of your parents had a stroke, you are at greater risk as well, either because of genetics or shared lifestyle traits.

While you can't do anything about non-modifiable risk factors it's helpful to know if you fall into a high-risk group so you can carefully monitor controllable factors.

July 2002 Update

Blood Pressure Medication May Affect Stroke Risk

Your choice of high blood pressure medication may affect your risk of stroke. Research published in the March 23, 2002, issue of The Lancet comparing the effectiveness of two high blood pressure is the first with solid evidence showing the importance of how we treat high blood pressure.

In the trial, called the LIFE study, researchers compared the number of strokes, heart attacks, and deaths due to cardiovascular events in over 9,000 patients taking either losartan or atenolol.

According to the results, both losartan and atenolol decreased blood pressure effectively, but patients who took losartan had a 25% lower risk of stroke than patients taking atenolol. In an accompanying study, researchers found similar results in patients with diabetes and high blood pressure.

Researchers believe the difference in effectiveness may be a result of the mechanisms by which each drugs works. Losartan belongs to a newer class of drugs, called angiotensin II receptor blockers (ARBs). ARBs lower blood pressure by preventing the smooth muscles of the arteries from contracting. Atenolol, on the other hand, is a beta-blocker and works to lower blood pressure by blocking substances that would otherwise speed up the heart and increase the pressure at which it pumps blood.

Results of the LIFE study also showed that losartan provided benefits beyond lowering blood pressure and reducing cardiovascular events. Patients on this drug had a 25% lower incidence of new-onset diabetes compared to patients on atenolol. In addition, patients in the losartan group were less likely to discontinue the drug due to side effects than were patients in the atenolol group.

Based on these findings, losartan or another ARB may quickly become a vital part of the first line of treatment for high blood pressure. Up until now, treatment with a beta-blocker, such as atenolol, and a diuretic has been regarded as the best intervention. The results of an upcoming National Institutes of Health study (due out in December) comparing a larger array of high blood pressure medications may shed even more light on the subject.

June 2002 Update

White-Coat Hypertension

Most people feel a bit anxious during a doctor's visit. But for some people, their anxiety causes temporary high blood pressure, detectable during the time of the visit. Physicians have been debating whether or not they should treat this phenomenon, referred to as "white-coat" hypertension. Some believe the short-lived blood pressure elevation is harmless, while others believe it should be treated like persistent high blood pressure.

In a recent study, researchers compared changes in the heart's function and size among people with persistent, untreated high blood pressure, "white coat" high blood pressure, and normal blood pressure. Participants were carefully matched by age, sex, and weight, as well as in-clinic and out-of- clinic blood pressures. Results of the study show participants with "white coat" hypertension, when compared to participants with normal blood pressure, had thicker walls in portions of their hearts, increased heart mass, and alterations in the diastolic (relaxing) portion of the heartbeat. Those people with persistent high blood pressure had even greater changes in the heart. These findings suggest "white coat" hypertension, while a temporary condition, may cause damage to the heart. This study reinforces the argument for treating "white coat" hypertension.

If you experience this condition, you should consult your doctor about treatment options. Simple lifestyle changes may be all you need or medication might be necessary. In any case, the possible benefits will outweigh the risks.
January 2002 Update

High-Normal Blood Pressure Bad for the Heart

People with high-normal blood pressure are more likely to suffer a heart attack, stroke, or heart failure than those with lower blood pressure, according to recent findings from the Framingham Heart Study.

The researchers followed the cardiovascular events of 6,859 participants of the famed study, which has been monitoring subjects from the Boston suburb for more than 50 years. A third of participants had normal blood pressure (120–129 over 80-84 mm HG), a quarter had high-normal (130–139 over 85–89 mm Hg), and the remainder had optimal blood pressure (less than 120 over less than 80 mm HG). People with high blood pressure were excluded from the study.

Of those in the optimal category, 81 had cardiac events, over a ten-year time period, compared to 136 people in the normal blood pressure category and 180 in high-normal category. In all, people with high-normal blood pressure were two to three times more likely to suffer a heart attack, stroke, or heart failure than those with lower blood pressure. This held true in both men and women, and was consistent in both age groups (35 to 64 and 65 and over), even after researchers adjusted for other cardiovascular risk factors such as smoking and obesity. Indeed, the study found risk increases in a stepwise fashion as blood pressure increases.

Blood pressure reflects how hard your heart is working and what conditions your arteries are in. Risk factors include heavy drinking, smoking, eating a diet high in salt, obesity, and family history. Doctors generally get alarmed only if systolic blood pressure is above 140 mm Hg or if diastolic blood pressure is above 90 mm Hg. However, this study calls for further research to be done to see if patients in the high-normal group benefit from lowering their blood pressure.
December 2001 Update

Salt Restriction More Potent Than Exercise

Physicians often give patients with hypertension a daunting list of lifestyle changes to help lower their blood pressure: lose weight, exercise more, eat less salt, drink less alcohol, eat more foods rich in calcium, potassium, and magnesium. Of course, these changes do work — people who follow them can reduce their need for medications or even do without blood pressure-lowering drugs. But which of these lifestyle changes gives you the biggest bang for your buck?

University of Colorado researchers recently compared the impact of exercise or moderate salt restriction in 35 healthy older women with high-normal blood pressure or mild hypertension (systolic blood pressure 130–159 mm Hg), none of whom were using drugs to lower their blood pressure. Half the women exercised for three months — starting at 30 minutes a day three or four times a week and working up to 45 minutes a day every day, if possible. The other half tried to reduce their daily salt intake to less than 2.4 grams of sodium (the amount in a level teaspoon of table salt) without otherwise changing their diets. All were asked to try to avoid gaining or losing weight.

The clear winner, reported in the American Journal of Cardiology, was sodium restriction. Among the women who ate less salt, average systolic blood pressures fell 16 mm Hg, compared with a still-respectable 5 mm Hg in the exercise group. By the study's end of the study, systolic blood pressure was lower in 88% of the women who ate less salt and in 55% of the exercisers.

So if you're trying to lower your blood pressure, should you just forget about exercise and work harder at eating less salt? No. Exercise has other benefits besides lowering blood pressure — it can help control weight, improve the cholesterol profile, stave off diabetes, and keep bones strong. The real message from this study is that everyone should exercise, but that people who are trying to control blood pressure should lower their sodium intake, too.
December 2001 Update

High Blood Pressure Drug Performs No Better Than Standard Treatment

An FDA advisory panel has decided to inform doctors about the results of a government study that found Cardura (doxazosin), a popular blood pressure medication sold by Pfizer, was less effective than a generic diuretic (chlorthalidone) in reducing some forms of cardiovascular disease. But the panel also concluded the agency didn't need to extend this warning to patients.

Cardura, which has been on the market for 10 years, is an alpha-adrenergic receptor blocker that relaxes smooth muscle throughout the peripheral parts of the body, including the blood vessels. It's often used for the management of hypertension, a condition involving persistently high arterial blood pressure. Hypertension is a major risk factor for the development of coronary heart disease, heart attacks and strokes.
Cardura's role in managing hypertension was investigated as part of the National Institute of Health's Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), the first large-scale blood pressure treatment study to compare several newer drug treatments with a cheaper generic diuretic.

The first part of ALLHAT was stopped early because users of Cardura had 25% more cardiovascular events and were twice as likely to be hospitalized for congestive heart failure as users of the diuretic. But the study didn't find Cardura users were any more likely to die than those using the diuretic. As a result, the NIH advised high blood pressure patients who now take Cardura consult with their doctors about a possible alternative. They also suggested the drug may not be the best choice for new patients. The American College of Cardiology followed with a clinical alert that advised physicians to stop prescribing Cardura and reassess its treatment value.

Last year, a group of patients filed a lawsuit with a U.S. District court claiming Pfizer did little to inform doctors and patients about the results of ALLHAT, but the petition was handed over to the FDA. The FDA advisory panel concluded that while it appeared the diuretic was more effective than Cardura in preventing congestive heart failure, there was not enough data to prove Cardura was harmful. The FDA often follows the recommendations of its advisory panels. Pfizer continues to maintain that Cardura is safe.
July 2001 Update

Statins Reduce C-reactive Protein

Half of all heart attack victims have normal cholesterol levels. Consequently, doctors are looking for new methods to improve heart disease prevention. One promising new approach involves testing for high levels of the inflammation marker C-reactive protein to identify people who might benefit from drug therapy.

C-reactive protein (CRP) is secreted from the liver in response to inflammation in the body. Because atherosclerosis is partly an inflammatory process, high levels of CRP have been shown to predict the risk of heart disease. A new study has found that statins can reduce the risk of coronary events in people who have high levels CRP. These drugs are already used to lower LDL cholesterol, but the researchers found its anti-inflammatory effect was independent of its cholesterol-lowering abilities.

The five-year randomized trial done at Brigham and Women's Hospital and Harvard Medical School involved 5,742 participants. The researchers found that Lovastatin decreased both CRP levels by an average of 14.8% and the rates of coronary events. Other statins has also previously been shown to reduce CRP levels.

This study suggests statins may be an effective preventive therapy for people with high CRP levels — even if they have low or normal LDL cholesterol. Though everyone is encouraged to make healthy lifestyle changes to reduce their heart disease risk, only those at high-risk are candidates for these costly drugs. And measuring CRP levels in conjunction with cholesterol testing should better identify these high-risk individuals.
July 2001 Update

Does Aspirin Prevent Preeclampsia?

Preeclampsia, also known as toxemia, is a condition that affects pregnant women and their unborn baby. It is characterized by high blood pressure, water retention, and protein in the urine. The condition, which usually occurs after the 5th month of pregnancy, can lead to seizures, kidney and liver damage, slow fetal growth, and even fetal or maternal death. Preeclampsia affects up to 8% of pregnancies, and is responsible for 10-15% of maternal deaths. In the past decade, several studies have looked at the effectiveness of aspirin in preventing preeclampsia.

Early studies showed promising results. But larger, more recent studies failed to show any benefit.

In an effort to reconcile these conflicting results, British researchers reviewed several studies involving over 30,000 women who were at increased risk for preeclampsia. (Risk factors include preexisting high blood pressure, diabetes, a first pregnancy, pregnancy as a teenager or over the age of 40, and pregnancy involving multiple fetuses.) The women had been randomized to receive an antiplatelet drug (usually low-dose aspirin), a placebo, or no antiplatelet medication.

The researchers concluded that aspirin reduced the risk of preeclampsia by 15%. Their review also showed that aspirin decreased the risk of premature births by 8% and the risk of stillbirths or newborn deaths by 14%. Based on these results — acknowledged by the researchers as showing only small to moderate benefits — the researchers recommended the use of aspirin. Several issues including the optimal dosage, the proper time to start treatment, and which women are most likely to benefit, remain unresolved.

Despite the results of this review, some leading experts are unconvinced that aspirin is effective at preventing preeclampsia. However, even physicians who doubt aspirin's efficacy agree that at doses of less than 80 milligrams per day, aspirin is not harmful. If your physician prescribes aspirin to prevent preeclampsia, it may or may not be effective — but in any case, it won't be harmful.
March 2001 Update

Low-Sodium DASH Diet Lowers Blood Pressure

The effect of reducing dietary salt on controlling hypertension, or high blood pressure, has been surprisingly controversial. But in a recent study, a collaboration of scientists, including researchers from Harvard Medical School and the National Heart, Lung, and Blood Institute of the National Institutes of Health, suggest that reducing salt intake may dramatically lower blood pressure in people with or without hypertension, regardless of age, race, or gender.

The trial, known as the Low-Sodium DASH Diet study, tested the effects on blood pressure of lower levels of sodium intake combined with the Dietary Approaches to Stop Hypertension (DASH) diet, which is low in fat and rich in fruits, vegetables, whole grains, and low-fat dairy products. More than 400 subjects were assigned either a typical American diet or the DASH diet for 12 weeks. The salt content of every participant's diet was randomly changed every four weeks to one of three sodium levels: high (3,300 mg), intermediate (2,400 mg), or low (1,500 mg).

The researchers found that with either diet, the lower the salt intake, the lower the blood pressure. But at each sodium level, blood pressure was consistently lower for those on the DASH diet. Moreover, the largest reductions in blood pressure were found among those who followed the DASH diet while consuming 1,500 mg of salt per day, well below the government's recommended daily intake of 2,400 mg, or 1 1/4 teaspoons. This combination worked best for all participants, but particularly for patients with hypertension, whose systolic blood pressure was 11.5 millimeters of mercury (mm Hg) lower than hypertensive participants on the control diet with a high sodium level. The beneficial effect of a lower sodium diet was also more pronounced in women than men and in blacks than people of other races.

Controlling blood pressure reduces the risk of developing complications associated with hypertension, which include heart disease and stroke. New dietary guidelines from the American Heart Association recommend that everyone adopt an eating plan similar to the DASH diet and limit their sodium intake to less than 2,400 mg per day. Other things you can do to keep blood pressure in check include maintaining a healthy body weight, cutting down on dietary fat, and staying active.
January 2001 Update

Reduce High Blood Pressure, Reduce the Risk of Dementia

High systolic blood pressures (when the top blood pressure number is above normal) in elderly people increases the chances that they will develop the diminished mental capacity known as dementia. Certainly this makes sense. High blood pressure damages blood vessels. When the blood supply to the brain is compromised, there may be damage to the brain tissue. Sometimes this damage is very abrupt, such as in the loss of function that may accompany a stroke. Other times, the damage is recognized gradually, as a person slowly loses some mental capabilities. This is the case with vascular dementia.

A major European study tested the theory that treating high blood pressure might reduce the incidence of dementia in elderly people. One-hundred-six centers in 19 countries enrolled 3,162 patients in this trial. Investigators randomly assigned these patients to receive either medicine to help lower blood pressure or a placebo and then followed the health of these individuals for two years. The results were so compelling that the study was stopped early. In this study, treatment of high systolic blood pressure reduced the incidence of dementia by 50%. Put another way, treating 1,000 patients with high blood pressure, over five years, could prevent 19 cases of dementia.

Researchers are just beginning to understand the physiology of dementia and how we might slow or prevent this process. Controlling high blood pressure is an important part of staying healthy for many reasons, for mind as well as body. For more information on dementia, see page 362 in the Family Health Guide.

High Blood Pressure Drugs and Diabetes Risk

Past studies have suggested that two types of drugs used to treat high blood pressure also promote the development of type 2 diabetes. These results led doctors to think twice about prescribing thiazide diuretics and beta blockers to their patients at high risk for diabetes. But a new, extensive study shows thiazide diuretics do not appear to increase the risk of diabetes, while beta blockers may contribute. The data also suggest that perhaps the risk of developing type 2 diabetes is associated with high blood pressure itself, and not the medications used to treat it.

Thiazide diuretics and beta blockers are the first line of treatment for most people with high blood pressure. Both therapies reduce the risk for strokes and heart attacks and have been shown to help people with high blood pressure live longer. Thiazide diuretics such as hydrochlorothiazide and chlorthalidone decrease blood pressure by reducing the volume of fluid in the body. Beta blockers such as propanolol and atenolol decrease blood pressure by blocking the nervous system’s response to stress and thereby relaxing the heart muscle. Earlier studies suggested that both drug classes might affect glucose tolerance and lead to diabetes, but a more recent study suggests something different.

To determine the relationship between the use of antihypertensive medications and the risk of developing diabetes, researchers in the U.S. followed 12,550 nondiabetic adults. They evaluated 3,804 hypertensive and 8,746 nonhypertensive patients for signs of diabetes three and six years later. Results showed that adults with high blood pressure (treated or untreated) were 2.5 times more likely to develop diabetes than were adults without hypertension. The scientists also analyzed the results by medication. The risk of developing diabetes was 28% greater for patients taking beta blockers than for patients taking no medication, regardless of hypertension. Patients taking other drugs to treat their hypertension were not at an increased risk.

The researchers pointed out that their study was limited by the lack of information regarding the dosage and duration of treatment with antihypertensive drugs. In addition to this, their results may have been affected by the perceived risk of diabetes and its influence on what drugs doctors prescribe. But the study was an improvement on past studies that were smaller and influenced by confounding factors.

In light of the results, doctors can now easily identify a group of patients at high risk for developing diabetes — those that take beta blockers — and perhaps help them develop a prevention program. In addition, physicians should be reassured about prescribing thiazide diuretics. The study investigators noted that despite the apparent increase in risk for diabetes associated with beta blockers, these drugs do have proven benefits for people with heart disease, and that a careful weighing of the potential risks against known benefits is important.

Renal Artery Stenosis-Related High Blood Pressure: Angioplasty vs. Medication

For many people with difficult to control high blood pressure, the problem really begins with (or is made worse by) narrowing of the arteries that supply the kidneys (renal stenosis). One way to manage the resulting elevations in blood pressure is with antihypertensive medications. Another way is balloon angioplasty — the same procedure used to clear narrowed or blocked coronary arteries, but applied to the renal arteries. A study conducted in the Netherlands compared the effects of balloon angioplasty with that of medical therapy (medication) on high blood pressure caused by renal stenosis.

Patients in this study had similar blood pressure levels and took similar doses of high blood pressure drugs at the beginning of the trial. Researchers then randomly assigned these volunteers to two groups. One group continued the two-drug regimen they had been taking, but could take a higher dose of a drug or add a drug, as needed; the other group continued to take a two-drug regimen and were also assigned to undergo balloon angioplasty.

The blood pressure of study participants was measured at three months and at 12 months. At three months, there was no significant difference in blood pressure between the two groups of patients. Also at three months, nearly half of the patients in the drug-therapy group had received balloon angioplasty either because drug therapy failed to adequately reduce blood pressure or because they showed signs of worsening kidney function. Nevertheless, the patients who only received drug therapy did not have higher blood pressure than those who underwent balloon angioplasty did.

Researchers concluded that, compared with antihypertensive drugs, balloon angioplasty does not always result in better blood pressure control for patients with renal stenosis. In patients whose high blood pressure cannot be controlled even when they take three or more medications or those for whom the renal-artery blockages worsen, balloon angioplasty serves only to lower blood pressure to the level that can be achieved by drug therapy in other patients. In only a very few cases did balloon angioplasty cure hypertension.
October 2000 Update

Ramipril for Diabetics with Heart Disease

The incidence of heart disease in the general population has been dropping. This is good news of course, but for individuals with diabetes, the statistics are not so promising. In fact, men with type 2 diabetes have experienced only a modest decline in heart disease rates, while women with diabetes have actually experienced an increase.

Heart disease accounts for 70% of deaths in people with diabetes. So, the outcome of a recent study, which demonstrated that the angiotensin-converting enzyme (ACE) inhibitor, ramipril, significantly lowered the incidence of heart disease, stroke, and death in people with diabetes who had a history of heart disease and hypertension, should be welcome news.

The Heart Outcomes Prevention Evaluation (HOPE) study included people with and without diabetes. More than one-third of the participants had diabetes. Of the participants with diabetes, the average age was a little over 65 years old, and one-third were women. All had a history of heart disease and half had a history of high blood pressure as well. All study volunteers were randomly assigned to either ramipril or a placebo. While ramipril did not lower the blood pressure of participants much — as it was originally intended to do — it did lower their risk for heart attack by 22%, their risk for heart disease by 37%, and their risk for stroke by 33%. Other studies conducted to evaluate the effects of ACE inhibitors on blood pressure in people with diabetes have had similar outcomes.
October 2000 Update


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