The new $3.7 million, three-year educational effort is a follow-up to the landmark Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) and is being implemented in collaboration with the National High Blood Pressure Education Program (NHBPEP). Funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, the ALLHAT blood pressure study compared the effects of four major classes of medications to treat high blood pressure. More than 42,000 patients ages 55 and older participated. The main results were published in the Journal of the American Medical Association in December 2002 and played a central role in NHBPEP's revision of the clinical practice guidelines on high blood pressure released in May 2003 (Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure).
"It often takes years for the results of major studies to become part of standard health care," notes NHLBI director Elizabeth G. Nabel, MD. "The results of ALLHAT and the clinical guidelines could have an enormous impact on the health of millions of Americans. We are confident that by playing a more active role in sharing the information, we will be able to put the results into action more quickly and more effectively."
An estimated 65 million American adults – nearly one in three -- have high blood pressure. But, for more than two-thirds of them, blood pressure remains out of control. High blood pressure leads to more than half of all heart attacks, strokes, and heart failure cases in the United States each year, and it increases the risk of kidney failure and blindness. Clinical guidelines recommend that physicians work with patients to keep blood pressures below 140/90 mmHg, even lower for people with diabetes or kidney disease, and encourage all their patients to make healthy lifestyle changes, such as losing excess weight, becoming physically active, limiting alcoholic beverages, and following a heart-healthy eating plan, including cutting back on salt and other forms of sodium, and not smoking.
ALLHAT researchers reported in 2002 that, overall, diuretics are more beneficial than calcium channel blockers, angiotensin converting enzyme (ACE) inhibitors, or alpha blockers as initial treatment to lower blood pressure and to protect against adverse effects of high blood pressure. For patients with diabetes or with mildly elevated fasting glucose--a sign of pre-diabetes--diuretics are at least as effective, and in some cases more beneficial, than the other two classes of medications, according to ALLHAT findings published in June 2005.
In general, diuretics are well tolerated by patients, with few side effects. Sometimes called "water pills," diuretics reduce the amount of fluid in the body by helping the kidneys flush excess water and salt from the body.
The other medications lower blood pressure differently. Calcium channel blockers keep calcium from entering the muscle cells of the heart and blood vessels, causing the blood vessels to relax. ACE inhibitors prevent the formation of a hormone called angiotensin II, which normally causes blood vessels to narrow. Alpha blockers allow blood to pass more easily by reducing nerve impulses to blood vessels. However, ALLHAT found that participants taking alpha blockers had 25 percent more cardiovascular events and were twice as likely to be hospitalized for heart failure as those taking the diuretic. Because of these findings, the alpha blocker arm of the study was stopped early.
"Based on the results, the ALLHAT investigators recommend that in addition to lifestyle changes, diuretics should be the drug of choice for first line blood pressure treatment," says William C. Cushman, MD, chair of the ALLHAT Dissemination Committee and chief of Preventive Medicine at the Veterans Affairs Medical Center in Memphis. "Because most patients require more than one drug, diuretics should generally be part of any antihypertensive regimen."
Cushman cites another advantage for using diuretics. "They are much less expensive than the other two drug classes. For those stretching their budgets, taking a medicine which costs less than $100 a year is a very good thing."
In the past 20 years, however, prescriptions for newer, more costly medications began replacing diuretics. The newer drugs were shown to lower blood pressure and heart disease risk compared to placebo, but how the drugs compared to each other was unknown until ALLHAT. Analyses of prescribing trends suggest that prescriptions for diuretics have slowly begun to rise since the study ended and clinical guidelines have encouraged the use of diuretics either alone or in combination with other blood-pressure lowering medications.
"The guidelines were simplified and strengthened to emphasize the most effective ways to control blood pressure – starting with lifestyle changes and including diuretics when medication is needed," notes Jeffrey Cutler, MD, NHLBI senior advisor and ALLHAT project director.
The ALLHAT Dissemination Plan includes materials for investigator educators to lead small, interactive educational sessions with physician peers. Educators are asked to make at least one presentation per month. The sessions include discussions of the study results, current hypertension treatment guidelines, and common concerns in clinical practice. Each educator receives training, presentation slides and handouts, and materials such as posters and brochures for clinicians to use in their offices. The educators expect to reach nearly 30,000 physicians by September 2006.
The dissemination plan also provides materials to encourage patients to ask their health care providers about their blood pressure control and the medicines they take. Brochures, recipe books, and other tools to help patients adapt healthier lifestyles are also available.
NHLBI is part of the National Institutes of Health (NIH), the Federal Government's primary agency for biomedical and behavioral research. NIH is a component of the U.S. Department of Health and Human Services. NHLBI press releases and other materials including information about high blood pressure are available online at www.nhlbi.nih.gov.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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