SBP and Risk of Recurrent Stroke

In persons with a prior stroke, national guidelines suggest maintaining a normal blood pressure (BP), defined as systolic BP (SBP) of <120 mm Hg and a diastolic BP of <80 mm Hg. According to researchers, data specifically addressing the role of BP levels within the normal range for vascular risk reduction after stroke are limited. Recent studies have shown that there is no benefit in achieving more aggressive SBP targets in high-risk patients with diabetes. Based on those findings, interest in the existence and nature of the J-shaped association of BP with outcomes in patient groups at high risk for vascular disease has grown. It is generally perceived that a J-shaped association between outcome and BP may not exist for stroke, the vascular disease most highly correlated with BP. Researchers recently conducted a post hoc observational analysis designed to evaluate the independent association of BP maintained within a low-normal range versus a high-normal range with clinical outcomes among patients who recently experienced an ischemic stroke. They reported results of their analysis in the Journal of the American Medical Association [2011;306(19):2137-2144]. The researchers analyzed data from the Prevention Regimen for Effectively Avoiding Second Strokes (PROFESS) trial, a multicenter study that involved 20,330 patients ≥50 years of age who experienced an ischemic stroke within 120 days prior to randomization and whose condition was stable. The primary outcome measure was the first recurrence of stroke of any type; the secondary outcome measure was a composite of stroke, myocardial infarction, or death from vascular cause. Patients were recruited from 695 centers in 35 countries from September 2003 through July 2006; follow-up was 2.5 years (follow-up ended February 8, 2008). Patients were categorized based on their mean SBP level: very low–normal (<120 mm Hg; n=1918), low-normal (120-<130 mm Hg; n=3982), high-normal (130-<140 mm Hg; n=6004), high (140-<150 mm Hg; n=4520), and very high (≥150 mm Hg; n=3905). The mean age of study participants was 66.1 years and 36% were female. Specifically comparing the low–-normal SBP level group with the high-normal SBP level group, there was a much lower frequency of hypertension (53.7% vs 73.7%, respectively) and antihypertensive drugs (54.0% vs 65.8%), as well as much higher frequencies of use of an antiplatelet drug (72.4% vs 62.5%) and a lipid modifier drug (53.5% vs 46.0%), and treatment with telmisartan (68.7% vs 48.8%). In unadjusted analyses, the recurrent stroke rate (primary outcome) was highest in the very high SBP level group (14.1%; 95% confidence interval [CI], 13.0%-15.2%), followed by the high SBP group (8.7%; 95% CI, 9.9%-9.5%), the very low–normal SBP group (8.0%; 95% CI, 6.8%-9.2%), the low-normal SBP group (7.2%; 95% CI, 6.4%-8.0%), and then the high-normal SBP group (6.8%; 95% CI, 6.1%-7.4%). Occurrence of the secondary outcome followed a similar pattern, the researchers said. Results of multivariable analyses demonstrated that compared with the high-normal SBP level group, the risks of the primary outcome were significantly higher in the very low–normal SBP group (adjusted hazard ratio [AHR], 1.29; 95% CI, 1.07-1.56), in the high SBP group (AHR, 1.23; 95% CI, 1.07-1.41), and in the very high SBP group (AHR, 2.08; 95% CI, 1.83-2.37). Likewise, compared with the high-normal SBP level group, the risks of the secondary outcome were significantly higher in the very low–normal SBP group (AHR, 1.31; 95% CI, 1.13-1.52), in the low-normal SBP group (AHR, 1.16; 95% CI, 1.03-1.31), in the high SBP group (AHR, 1.24; 95% CI, 1.11-1.39), and in the very high SBP group (AHR, 1.94; 95% CI, 1.74-2.16). In summary, the researchers said, “among patients with recent non-cardioembolic ischemic stroke, SBP levels during follow-up in the very low–normal (<120 mm Hg), high (140-<150 mm Hg), or very high (≥150 mm Hg) range were associated with increased risk of recurrent stroke.”