Association of blood pressure indices and stroke mortality in isolated systolic hypertension.

BACKGROUND AND PURPOSE: Isolated systolic hypertension (ISH), systolic blood pressure (BP) > or =160 mm Hg and diastolic BP (DBP) <90 mm Hg, is associated with stroke; however, the correlation between specific BP indices and stroke mortality in ISH is not defined. METHODS: In a pooled analysis of 9 epidemiological studies, we examined whether pulse pressure (PP) was more predictive of stroke mortality than systolic BP (SBP), DBP, or mean BP (MAP) in persons with ISH. Subjects (n=682; 29% male; 77% white; mean age 63.6 years) with ISH, free of cardiovascular disease, and not on antihypertensive drug therapy at baseline were followed a mean of 13.0+/-7.3 years, and 54 stroke deaths occurred. The relative importance of each BP index was compared by the decrease in the -2 log likelihood (a measure of model agreement with data) because of the addition of 1 or a combination of BP indices to a Cox regression model. Hazards ratios (HRs) for fatal stroke for a 1-SD in BP index were determined. RESULTS: PP was the best predictor of stroke mortality based on the decrease in the -2 log likelihood (10.65; P=0.001; HR=1.52), followed by SBP (7.19; P=0.007; HR=1.40), DBP (2.76; P=0.10; HR=0.80), or MAP (0.39; P=0.39; HR=1.10). Any combination of BP indices did not exceed a decrease in the -2 log likelihood of 10.72. CONCLUSIONS: These data suggest that in persons with ISH, PP is a better predictor of fatal stroke than SBP, DBP, or MAP.