December 14, 2004

CHICAGO (AP) -- Older women who combine two popular blood pressure drugs might be raising their risk of death, according to a study of more than 30,000 women. But doctors warned the research has flaws and said it is too soon to know whether the commonly prescribed duo really is dangerous.

In the study, women who combined diuretics with calcium channel blockers -- among the most frequently prescribed drugs for high blood pressure -- had nearly twice as many fatal heart attacks and other cardiovascular deaths as women on diuretics plus beta blockers or ACE inhibitors.

Still, the number of heart-related deaths was relatively small: 31 out of 1,223 women taking the calcium channel blocker combination versus 18 out of 1,380 on the beta blocker combination and 17 out of 1,413 on the ACE inhibitor duo.

Patients frequently need to take more than one drug to keep blood pressure down.

Dr. Ernesto Schiffrin, former head of the American Heart Association's high blood pressure council and professor of medicine at the University of Montreal, said the study "has major limitations and should not be taken at face value."

Calcium channel blockers are among the most potent hypertension drugs, and it is possible women taking them with diuretics were sicker and already faced an increased risk of death, Schiffrin said. He also noted that the study was based only on observations and was not a randomized trial -- the gold standard of medical research -- in which participants are randomly assigned treatment.

Sylvia Wassertheil-Smoller, a researcher at Albert Einstein College of Medicine and the study's lead author, acknowledged the limitation but said the results are a concern and should be investigated in a randomized study.

In the meantime, she advised older women on the two-drug combination to question their doctors about why they prescribed calcium channel blockers.

Calcium channel blockers relax blood vessels and reduce the heart's workload by affecting the movement of calcium into cells. Diuretics rid the body of excess sodium and water, lowering blood volume and thereby reducing the heart's workload.

The government-sponsored study appears in Wednesday's Journal of the American Medical Association.

The study involved 30,219 women ages 50 to 79 with hypertension but no history of cardiovascular disease, including 18,969 who were taking at least one blood pressure drug. The researchers followed the women for an average of nearly six years.

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