MUSC Medical Links Charleston Links Archives Medical Educator Speakers Bureau Seminars and Events Research Studies Research Grants Catalyst PDF File Community Happenings Campus News

Return to Main Menu

Diuretics lower blood pressure in blacks with metabolic syndrome

New research shows that diuretics are as protective in people with high blood pressure who suffer a cluster of conditions that increase the risk for heart disease as newer, more expensive medications.
The findings run counter to current medical practices that favor angiotensin-converting enzyme (ACE)-inhibitors, alpha-blockers, and calcium channel blockers for treatment of high blood pressure in those with the heart risk factor, metabolic syndrome, particularly among blacks.
The latest findings from the Anti-hypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT), sponsored by the National Heart, Lung, and Blood Institute (NHLBI), were published in the Jan. 28 issue of Archives of Internal Medicine.
ALLHAT is the largest study to compare a diuretic (chlorthalidone) with three newer classes of medications to treat high blood pressure: a calcium-channel blocker (amlodipine besylate); an alpha-blocker (doxazosin mesylate); and an ACE inhibitor (lisinopril). Each drug was used to start treatment, and other medications could be added if necessary to control blood pressure. The study originally reported in 2002 that diuretics were the most beneficial of the drug classes studied for treating high blood pressure and for protecting against adverse cardiovascular outcomes.
This latest analysis shows that even among adults with metabolic syndrome, and for black and non-black participants, the less costly diuretics consistently control blood pressure and are equally beneficial in preventing heart attack and coronary heart disease death. They are also more beneficial than newer medications in preventing one or more other forms of cardiovascular disease, including heart failure and stroke.
Another ALLHAT paper, reported in the February issue of Diabetes Care, reached similar conclusions when patients with diabetes were excluded.
People with metabolic syndrome have three or more risk factors for heart disease, including elevated blood pressure, low good cholesterol levels, and diabetes or pre-diabetes.
When compared with those taking diuretics, black participants with metabolic syndrome receiving ACE-inhibitors had poorer blood pressure control and a 24 percent greater risk of overall cardiovascular disease. This included a 19 percent greater risk of coronary heart disease, a 37 percent greater risk of stroke, and a 49 percent greater risk of heart failure. They also had a 70 percent greater risk of kidney failure.
“In black patients with high blood pressure and metabolic syndrome, the evidence from ALLHAT overwhelmingly supports the choice of thiazide-type diuretics,” said Jackson Wright Jr., M.D., Ph.D., professor of medicine, Case Western Reserve University, the study’s lead author.

What is metabolic syndrome?
Metabolic syndrome is characterized by a group of metabolic risk factors in a person that include:
  • Abdominal obesity (excessive fat tissue in and around the abdomen)
  • Atherogenic dyslipidemia (blood fat disorders— high triglycerides, low HDL cholesterol and high LDL cholesterol—that foster plaque buildups in artery walls)
  • Elevated blood pressure
  • Insulin resistance or glucose intolerance
  • Prothrombotic state (e.g., high fibrinogen or plasminogen activator inhibitor–1 in the blood)
  • Proinflammatory state
People with metabolic syndrome are at increased risk of coronary heart disease and other diseases related to plaque buildups in artery walls (e.g., stroke and peripheral vascular disease) and Type 2 diabetes. The metabolic syndrome has become increasingly common in the United States. More than 50 million Americans are believed to have it.
The dominant underlying risk factors for this syndrome appear to be abdominal obesity and insulin resistance. Insulin resistance is a generalized metabolic disorder in which the body can’t use insulin efficiently. (Metabolic syndrome is also called the insulin resistance syndrome.)
Other conditions associated with the syndrome include physical inactivity, aging, hormonal imbalance and genetic predisposition.
Some people are genetically predisposed to insulin resistance. Acquired factors, such as excess body fat and physical inactivity, can elicit insulin resistance and the metabolic syndrome in these people. Most people with insulin resistance have abdominal obesity.
The primary goal of clinical management of the metabolic syndrome is to reduce the risk for cardiovascular disease and Type 2 diabetes. Then, the first-line therapy is to reduce the major risk factors for cardiovascular disease: stop smoking and reduce LDL cholesterol, blood pressure and glucose levels to the recommended levels.
For managing long- and short-term risk, lifestyle therapies are the first-line interventions to reduce the metabolic risk factors. These interventions include weight loss to achieve a desirable weight; increased physical activity, with a goal of at least 30 minutes of moderate-intensity activity on most days of the week ; and healthy eating habits.

Friday, Feb. 22, 2008
Catalyst Online is published weekly, updated as needed and improved from time to time by the MUSC Office of Public Relations for the faculty, employees and students of the Medical University of South Carolina. Catalyst Online editor, Kim Draughn, can be reached at 792-4107 or by email, Editorial copy can be submitted to Catalyst Online and to The Catalyst in print by fax, 792-6723, or by email to To place an ad in The Catalyst hardcopy, call Island Publications at 849-1778, ext. 201.