UW News

November 12, 2002

Half of older adults with high blood pressure don’t have it under control, and face significant risks

At least half of older adults with hypertension do not have their blood pressure controlled to normal levels, according to a survey of 5,888 patients around the country. The failure to control blood pressure to less than 140/90 mmHg may account for as much as 22 percent of myocardial infarctions and 34 percent of strokes in older adults, according to University of Washington researchers.

These are the conclusions of a study that will be published in this week’s edition of Archives of Internal Medicine.

The study may well be underestimating the overall proportion of people who are undertreated or not treated for hypertension. In the study, every participant’s blood pressure was measured each year; if the patient had high blood pressure, both the patient and the patient’s physician were notified. Even with annual notices about high levels of blood pressure, half of the patients have not had their blood pressure brought under control.

That’s particularly tragic because, researchers say, the first line of defense against high blood pressure is low-dose diuretics, which are safe and effective when used properly; a month’s supply of diuretics costs less than a latte.

“For less than the price of a single coffee each month, people with untreated high blood pressure could prevent devastating complications such as stroke, heart attack or heart failure,” says Dr. Bruce M. Psaty, lead author of the study and a professor of medicine, epidemiology and health services and co-director of the UW’s Cardiovascular Health Research Unit.

“The data clearly show that for older adults, there is less than optimal control of blood pressure, especially for systolic blood pressure. High levels of systolic blood pressure are strongly associated with disease risk, and we have safe and effective blood-pressure treatments that reduce the risk of heart attack and stroke,” Psaty says.

(Systolic blood pressure is the upper reading; the recommended maximum is generally 140 mmHg. The study did not address why systolic blood pressure might be receiving less emphasis among patients and in clinics.)

The subjects came from the Cardiovascular Health Study, 5,888 adults 65 or older from four parts of the country who were studied in either 1989 or 1990 and then every year through 1998 or 1999.

The study also analyzed trends over time in the medications that the patients were taking. Low-dose diuretics are currently recommended as first-line drug therapy for hypertension by the U.S. Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure. In older adults free of coronary disease, the proportion taking a thiazide diuretic declined from 60 percent in 1990 to 38 percent in 1999. Low-dose diuretics are known to be safe and effective in older adults. Yet their use declined while the use of other more expensive drugs, including angiotensin converting enzyme (ACE) inhibitors and calcium-channel blockers, increased.

“This pattern of use is not endorsed by national guidelines,” Psaty says. He advises, “If you are on treatment for high blood pressure, and if you are not taking a low-dose diuretic, it is reasonable to ask your physician, ‘Why not?'”

This study was funded by grants from the National Heart, Lung and Blood Institute and the National Institute on Aging.

Other authors of the paper are Dr. Nicholas L. Smith and Susan R. Heckbert, UW Department of Epidemiology, and Dr. Thomas Lumley, UW Department of Biostatistics, all in the School of Public Health and Community Medicine; Dr. Curt Furberg and Dr. Greg Burke, Wake Forest University School of Medicine; Dr. Teri A. Manolio, National Heart Lung and Blood Institute; Dr. John Gottdiener, St. Francis Hospital, Roslyn, N.Y.; Dr. Joel Weissfeld, University of Pittsburgh; Dr. Paul Enright, Respiratory Sciences Center, University of Arizona, Tucson; and Dr. Neil Powe, Johns Hopkins University.