Findings Link Variability in Blood Pressure, Stroke Risk
Research makes 'strong argument' for measuring BP variability in addition to mean pressure
FRIDAY, March 12 (HealthDay News) -- Variability in systolic blood pressure (SBP) from visit to visit and maximum SBP are predictors of stroke, and the effect of drug classes on interindividual variation in blood pressure may explain the different effects of antihypertensive drugs on stroke risk, according to research published in the March 13 issue of The Lancet.
Peter M. Rothwell, M.D., of the John Radcliffe Hospital in Oxford, U.K., and colleagues analyzed data from patients with previous transient ischemic attack (TIA) and patients with treated hypertension. They found that, among TIA patients, visit-to-visit variability in SBP predicted later stroke, independent of their mean SBP. Maximum SBP also predicted stroke. In patients with treated hypertension, residual variability in SBP from visit to visit during treatment predicted stroke and coronary events, independent of mean SBP.
Alastair J.S. Webb, also of the John Radcliffe Hospital, and colleagues performed a meta-analysis of 389 randomized controlled trials that compared the effects of antihypertensive drugs. They found that calcium-channel blockers and non-loop diuretic drugs decreased interindividual SBP variation compared to other classes, and angiotensin-converting enzyme inhibitors, angiotensin-2 receptor blockers, and beta blockers increased it. The effect of treatment on interindividual SBP variation was linked to the effect on stroke risk, independent of differences in average SBP.
"Importantly, Rothwell and co-workers do not question the importance of mean blood pressure; rather, they make a strong argument for also measuring blood-pressure variability because it supplements blood pressure very well as a risk factor," write the authors of an accompanying commentary.
Several authors of the first study reported financial relationships with pharmaceutical companies.