NEW YORK (Reuters Health) – Lowering blood pressure in patients with prehypertensive blood pressure significantly reduces the risk of stroke, according the results of a meta-analysis reported in the December 8th online issue of Stroke.“To prevent 1 stroke, 169 patients had to be treated with a blood-pressure-lowering medication for an average of 4.3 years,” the authors found.Dr. Ilke Sipahi, with Case Western Reserve University School of Medicine in Cleveland, Ohio, and colleagues note that while it is well established that blood pressure reduction in hypertensive patients reduces cardiovascular events including stroke, the traditional definition of hypertension as a blood pressure of 140/90 mm Hg and higher is arbitrary. A prehypertensive blood pressure of 120-139/80-89 mm Hg is associated with an increased risk of stroke, they continue, but it is unknown if antihypertensive treatment in this range is beneficial.To examine that question, the team identified 2852 trials involving 95 different antihypertensive agents, and excluded those with an average baseline blood pressure of 140/90 mm Hg or greater, as well as other disqualifying criteria.The remaining 16 randomized, double-blind trials involved 70,664 patients. Angiotensin-converting enzyme inhibitors were studied in eight trials, angiotensin receptor blockers in four trials, calcium channel blockers in two, and a calcium channel blocker and/or an angiotensin-converting enzyme inhibitor in two trials. The pooled analysis indicated that active treatment led to a statistically significant reduction in the risk of stroke compared with placebo, (relative risk 0.78; p<0.000001); the researchers report.Furthermore, the risk of stroke was reduced with antihypertensive treatment of even lower baseline pressures. When the team looked at only trials in which the average baseline BP was less than 130/85 mm Hg, the relative risk of stroke with treatment versus placebo was 0.65 (p=0.048), the report indicates.Stroke risk was reduced with all classes of antihypertensive agents, Dr. Sipahi and colleagues found.“The number needed to treat obtained from this meta-analysis (169 patients for 4.3 years) should be viewed in the context of the number needed to treat of 642 patients for 5 years to prevent 1 stroke with statin therapy for primary prevention,” they comment.All in all, they conclude, “These findings can have important clinical implications.”Reference:Effect of Antihypertensive Therapy on Incident Stroke in Cohorts With Prehypertensive Blood Pressure LevelsStroke. 2012;43.
