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

Background and Purpose - Isolated systolic hypertension ( ISH), systolic blood pressure ( BP) >= 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. Conclusion - These data suggest that in persons with ISH, PP is a better predictor of fatal stroke than SBP, DBP, or MAP.