The
Systolic Hypertension in the Elderly Program (SHEP) is a randomized, blinded test of the efficacy of
antihypertensive drug treatment. In a large feasibility trial, 551 men and women who had
isolated systolic hypertension and were at least 60 years old received
chlorthalidone (25 to 50 mg/day) or matching placebo as the step I
drug. After 1 year, 83% of the
chlorthalidone group and 80% of the placebo group were still taking SHEP medications. Of those still taking
chlorthalidone, 88% had reached goal blood pressure (BP) without requiring a step II
drug, and most had responded to the lower dose (25 mg/day). The BP response was similar in all age, sex and race subgroups, with an overall mean difference between randomized groups of 17 mm Hg for systolic BP (p less than 0.001) and 6 mm Hg for diastolic BP (p less than 0.001). The only common adverse effects were asymptomatic changes in the serum levels of
potassium (0.5 mEq/liter lower in the
chlorthalidone group, p less than 0.001),
uric acid (0.9 mg/dl higher, p less than 0.001) and
creatinine (0.08 mg/dl higher, p = 0.02). This study indicates that
chlorthalidone is effective for lowering BP in elderly patients with
systolic hypertension and sets the stage for a larger trial of the effects of such treatment on the incidence of
cardiovascular disease.