Drug-resistant high blood pressure rising

High blood pressure, the most commonly diagnosed condition in the United States, is becoming increasingly resistant to drugs that lower it, according to a panel of experts assembled by the American Heart Association.

"It's becoming more difficult to treat, and it's requiring more and more medications to do so," said the panel chairman, Dr. David Calhoun, a hypertension specialist at the University of Alabama at Birmingham.

The problem is not that the medications have stopped working, said the report, published this month in the journal Hypertension. Instead, many blood-pressure patients are sicker to begin with and require more drugs, at greater dosages, to manage their conditions.

The doctors say this is especially worrisome because recent surveys estimate that one in three Americans have hypertension, an underlying cause of heart attacks, strokes, kidney disease and heart failure.

Starting at a blood pressure of 115/80, research shows that the risk of a heart attack or stroke doubles with every 20-point increase of systolic pressure, the top number, or 10-point increase of diastolic pressure, the bottom number.

"High blood pressure is currently the biggest single contributor to death around the world, because it is so common," said Dr. Neil Poulter of the International Center for Circulatory Health at Imperial College London. In the United States, it is particularly common among blacks, with 41 percent found to have it in a 2005 study, compared with 27 percent of whites.