Low-normal Systolic Blood Pressure and Secondary Stroke Risk

A recent observational study of >20,000 patients with recent ischemic stroke suggested that systolic blood pressure (SBP) maintained in a low-normal range may be associated with increased risk of recurrent stroke, especially within the first 6 months after the first stroke. Using a distinct cohort, the current study aimed to independently evaluate the relationship between low-normal SBP levels and risk of recurrent stroke through analysis of a trial dataset involving 3680 patients with recent noncardioembolic ischemic stroke aged ≥ 35 years recruited from 56 centers between September 1996 and May 2003 and followed for 2 years. Subjects were categorized based on their mean in-trial SBP value as low-normal (<120 mm Hg), high-normal (120 to <140 mm Hg), or high (>140 mm Hg). The primary outcome was stroke. Multivariate analyses used competing-risks Cox regression models. The rate of recurrent stroke was 9.1% in the low-normal group, 6.7% in the high-normal group, and 10% in the high group. The difference in recurrent stroke rate between the low-normal and high-normal groups was more prominent within the first 6 months (low-normal, 4.5%; high-normal, 2.5%; high, 3.4%) than after 6 months (low-normal, 4.6%; high-normal, 4.2%; high, 6.6%). Over the study period, compared with the high-normal group, the risk of the primary outcome trended higher in the low-normal group (adjusted hazard ratio, 1.47; 95% confidence interval, 0.94-2.29; P = .09) and was higher in the high group (adjusted hazard ratio, 1.39; 95% confidence interval, 1.08-1.79; P = .01). These results support the recently described pattern of increased risk of recurrent stroke in patients with low-normal SBP levels, especially within the first 6 months after first stroke. However, this study likely was not sufficiently powered to detect more than a strong statistical trend underlying this relationship.