Treatment with a low-dose diuretic to reduce high systolic blood pressure cuts strokes and heart attacks by a third in older patients with diabetes, according to results from a National Institutes of Health trial.
The Systolic Hypertension in the Elderly Program (SHEP) was a long-term, multi-center trial supported by the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute on Aging (NIA). These findings appear in the December 18, 1996, issue of the Journal of the American Medical Association.
"This trial shows clearly the benefits of diuretic treatment for older patients with diabetes and systolic hypertension," said NHLBI Director Dr. Claude Lenfant. "Hypertension increases the risk of vascular problems in these patients and needs to be controlled. This therapy should be considered as a first-choice treatment for them, along with lifestyle changes."
More than 3 million Americans over age 60 have isolated systolic hypertension. If untreated, they face as much as a threefold higher risk of stroke, other cardiovascular event, or death as those with normal blood pressures.
Earlier results from the trial had showed that treatment of ISH greatly reduces the incidence of stroke and other cardiovascular events and deaths in older persons generally. The analysis was published in the June 26, 1991, issue of JAMA.
However, that analysis did not specifically examine the effect of ISH treatment on those with diabetes, who have especially high heart disease death rates. Heart disease accounts for 75 percent of all deaths for those with diabetes. Middle-aged and older persons with diabetes have heart disease and stroke death rates two to four times higher than persons of the same age without diabetes. These risks are especially high when their blood pressure is elevated.
SHEP involved 4,736 men and women aged 60 and older with systolic blood pressures of 160 mmHg or above and diastolic pressures of under 90 mmHg. There were 583 patients with non-insulin-treated diabetes, 243 of whom were on an oral hypoglycemic medication.
Patients were randomly assigned to receive either a placebo or a low-dose diuretic (chlorthalidone) and, if needed, a second drug. The second drug was a low-dose of either a beta blocker (atenolol) or an adrenergic antagonist (reserpine). Patients were followed for an average of 4.5 years.
Both diabetic and non-diabetic patients fared much better on drug therapy than on the placebo. They had fewer strokes, heart attacks, other major cardiovascular events, and deaths from any cause. There were minimal differences in side effects among those taking drug therapy or the placebo.
But those with diabetes benefited most from the drug therapy. This was primarily because they had a higher risk of stroke and heart attack at the outset and so had more to gain from effective treatment. Overall, the 5-year reduction in cardiovascular events with treatment was 101 events for every 1,000 patients with diabetes and 51 events for every 1,000 patients without diabetes.
No data are available on the use of other antihypertensive drug regimens to reduce cardiovascular events among those with diabetes. To help find answers, the NHLBI is sponsoring the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). The nationwide trial will examine four main blood pressure-lowering drugs and expects to enroll 40,000 older patients, a third of them with diabetes. ALLHAT has a toll-free phone number -- 1-888-99HEART -- for patients seeking enrollment information.
The following SHEP principal investigators are available to comment on the trial: Dr. J. David Curb, of the University of Hawaii School of Medicine and the Pacific Health Research Institute in Honolulu; Dr. Jeremiah Stamler, of Northwestern University Medical School in Chicago, IL; and Dr. Jeffrey Cutler, Director of NHLBI's Clinical Applications and Prevention Program. Also available to comment is Dr. Stanley Slater, NIA Deputy Associate Director for Geriatrics and NIA Project Officer for SHEP. Dr. Curb can be contacted at (808) 524-4411; Dr. Stamler at (312) 908-7914; Dr. Cutler through the NHLBI Communications Office at (301) 496-4236; and Dr. Slater through the NIA Public Information Office at (301) 496-1752.