January 28, 2008

Diuretics Best for Hypertension and Metabolic Syndrome

MONDAY, Jan. 28 (HealthDay News) -- Diuretics appear to be as good or better than other blood pressure drugs for treating hypertension in patients with metabolic syndrome, especially black patients, according to a U.S. study.

People with hypertension and metabolic syndrome are at high risk for complications of cardiovascular disease.

Researchers at Case Western Reserve University and University Hospitals Cases Medical Center in Cleveland analyzed data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

It included 42,418 people with hypertension and at least one other risk factor for cardiovascular disease who were randomly assigned to take either the diuretic chlorthalidone (15,255), the calcium channel blocker amlodipine besylate (9,048), the alpha-blocker doxazosin mesylate (9,061), or the ACE inhibitor lisinopril (9,054).

Each drug was used to start treatment, and other drugs were added if necessary to control blood pressure. The majority of patients were followed for an average of 4.9 years, but the alpha-blocker part of the trial was halted after an average of 3.2 years due to increased rates of cardiovascular disease.

Among the patients in the study, 23,077 met the criteria for metabolic syndrome, which is defined as hypertension plus at least two of the following factors: diabetes or pre-diabetes; a body-mass index (BMI) of at least 30; high triglyceride levels; or low levels of high-density lipoprotein ("good" cholesterol).

"No differences were noted among the four treatment groups, regardless of race or metabolic syndrome status for the primary end point (nonfatal myocardial infarction [heart attack] and fatal coronary heart disease)," the study authors wrote.

Among patients with metabolic syndrome, those taking the diuretic had a lower rate of heart failure than those taking the other three drugs. Patients who took the ACE inhibitor and the alpha-blocker also had an increased risk of combined cardiovascular disease.

"The lack of benefit of the agents with the most favorable metabolic profile [i.e., ACE inhibitors and alpha-blockers] was especially marked in black participants with metabolic syndrome," the researchers wrote.

"The magnitude of excess risk of end-stage renal [kidney] disease [70 percent], heart failure [49 percent] and stroke [37 percent] and the increased risk of combined cardiovascular disease and combined coronary heart disease strongly argue against the preference of ACE inhibitors over diuretics as the initial therapy in black patients with metabolic syndrome. Similar high risk was noted for those randomized to the alpha-blocker versus the diuretic."

The researchers concluded that the findings "fail to provide support for the selection of alpha-blockers, ACE inhibitors, or calcium channel blockers over thiazide-type diuretics to prevent cardiovascular or renal outcomes in patients with metabolic syndrome, despite their more favorable metabolic profiles."

The study, which received support from Pfizer Inc., was published in the Jan. 28 issue of the Archives of Internal Medicine.

More information

The American Academy of Family Physicians has more about metabolic syndrome.

-- Robert Preidt
SOURCE: JAMA/Archives journals, news release, Jan. 28, 2008
id=612059