Stroke Risk Reduced With Treatment of Prehypertension
Medscape Medical News © 2011 WebMDDecember 8, 2011 — Patients with prehypertension who take blood pressure–lowering therapy have a highly statistically significant 22% reduced risk for stroke, a new meta-analysis shows.
The reduction in stroke risk observed in the study was "clear-cut," "clinically meaningful," and evident among all classes of antihypertensive drugs studied, said lead author Ilke Sipahi, MD, assistant professor of medicine, Case Western Reserve University, Cleveland, Ohio, and associate director, Heart Failure and Transplantation at University Hospitals Case Medical Center.
"We saw it with [angiotensin converting enzyme (ACE)] inhibitors, we saw it with calcium channel blockers, and we saw it with angiotensive-receptor blockers [ARBs] to a certain extent," Dr. Sipahi told Medscape Medical News. "So this is true finding: the risk is truly reduced."
However, the study results should not change current recommendations regarding blood pressure–lowering therapy, said Dr. Sipahi.
"It's not realistic to go ahead and recommend antihypertensive therapy to every single patient with prehypertensive blood pressure levels, but I think our findings have to be discussed extensively within the medical community."
Prehypertension is defined as a blood pressure of 120 to 139 mm Hg systolic and 80 to 89 mm Hg diastolic. Current guidelines recommend lowering blood pressure to 140/90 mm Hg or less.
The study was published online December 8 in Stroke, the Journal of the American Heart Association.
The reduction in stroke risk applied to all classes of antihypertensive therapy. Patients randomly assigned to receive ACE inhibitors or calcium channel blockers had about a 25% decreased stroke risk compared with placebo, whereas those taking an ARB experienced about a 15% reduced risk.
The investigators did not find trials that compared diuretics, alpha blockers, or beta blockers in a prehypertensive population. "So we don't know whether these drugs would have the exact same beneficial effect, in terms of risk reduction effect on stroke, in these patients," said Dr. Sipahi.
Prehypertension is quite common, occurring in up to 40% of the population, depending on the age, sex, and ethnicity of the population studied. Professional societies do not currently recommend pharmacological treatment for prehypertension because of the lack of prospective, randomized trials examining the effect of antihypertensive therapy to reduce cardiovascular events in this population.
The current analysis concluded that to prevent a single stroke, 169 patients had to be treated with a blood pressure–lowering medication for an average of 4.3 years. This number, said Dr. Sipahi, is "not huge," and is better than the number needed to be treated with a statin to prevent a stroke. It is estimated that 642 patients need to be treated for 5 years with a statin to prevent 1 stroke. "In that regard, antihypertensives are actually more cost-effective compared to statins for stroke in the setting of prehypertension," Dr. Sipahi noted.
As it stands, starting antihypertensive therapy in patients with blood pressures of 120 to 139 mm Hg may be advisable only in relatively high-risk patients with prehypertension, for example, those with a history of smoking, diabetes, or hyperlipidemia, said Dr. Sipahi.
However, for everyone else, such an approach may be "overkill," he said, adding that expanding blood pressure therapy to patients with prehypertension could be tremendously expensive. He also noted that blood pressure drugs can have adverse effects such as hyperkalemia, hypotension, and dizziness, especially in the elderly.
The analysis found no statistically significant decrease in myocardial infarction (MI) with antihypertensive therapy. However, there was a trend toward risk reduction for MI that was mainly driven by ACE inhibitor trials in patients at high risk, such as the Heart Outcomes Prevention Evaluation (HOPE) trial and the European Trial on Reduction of Cardiac Events With Perindopril in Stable Coronary Artery Disease (EUROPA), said Dr. Sipahi.
This, he said, was not surprising. "Stroke is very blood pressure–sensitive, and MI is more sensitive to hypercholesteremia."