Risk factors for stroke and type of stroke in persons with isolated systolic hypertension. Systolic Hypertension in the Elderly Program Cooperative Research Group.

BACKGROUND AND PURPOSE: We sought to determine risk factors for stroke and stroke type in persons with isolated systolic hypertension (ISH).

METHODS

We performed proportional hazards analyses of data from the Systolic Hypertension in the Elderly Program, a double-blind, randomized, placebo-controlled trial of 4736 persons aged > or =60 years with ISH (systolic blood pressure, 160 to 219 mm Hg; diastolic blood pressure, <90 mm Hg). One treatment group received chlorthalidone (12.5 to 25 mg/d) with step-up to atenolol (25.0 to 50.0 mg/d) or reserpine (0.05 to 0.10 mg/d), if needed. The other treatment group received matching placebo. The main outcome measures were stroke, stroke or transient ischemic attack [TIA], and stroke types: ischemic (including lacunar, atherosclerotic, and embolic) and hemorrhagic.

RESULTS

During an average follow-up of 4.5 years, 384 strokes or TIAs and 262 strokes (including 217 ischemic, 66 lacunar, 26 atherosclerotic, and 25 embolic strokes) were documented. In multivariate analyses, placebo treatment, older age, smoking, history of diabetes, higher systolic blood pressure, lower HDL cholesterol, and ECG abnormality were significantly associated (P<0.05) with increased incidence of stroke or TIA, stroke, or ischemic stroke. Greater lacunar stroke risk was significantly related to placebo treatment, older age, history of diabetes (relative risk [RR] = 3.03; 95% confidence interval [CI], 1.70 to 5.40), and smoking (RR = 3.04; 95% CI, 1.73 to 5.37). Greater atherosclerotic and embolic stroke risk were significantly related to presence of carotid bruit (RR = 5.75; 95% CI, 2.50 to 13.24) and older age (RR = 1.65 per 5 years; 95% CI, 1.25 to 2.18), respectively.

CONCLUSIONS

In older persons with ISH, history of diabetes and smoking are important risk factors for lacunar stroke, whereas carotid bruit and age are important risk factors for atherosclerotic and embolic stroke, respectively.