Prehypertension is associated with an increased risk for stroke, researchers reported online ahead of print March 12 in Neurology. The risk was observed even in persons with low-range prehypertension, although it was largely influenced by high-range prehypertension, according to Yuli Huang, MD, and colleagues.
“The results were consistent across stroke type, stroke end point, age, study characteristics, follow-up duration, and ethnicity,” said Dr. Huang, a researcher in the Department of Cardiology, Nanfang Hospital, Southern Medical University in Guangzhou, China.
The findings are based on a meta-analysis of 19 prospective cohort studies that included 762,393 patients. All eligible studies that were analyzed had reported multivariate-adjusted relative risks (RRs) with 95% confidence intervals for the associations between stroke and prehypertension or its two subranges—low-range prehypertension (120–129/80–84 mm Hg) and high-range prehypertension (130–139/85–89 mm Hg). Subgroup analyses were conducted according to blood pressure ranges, stroke type, end point, age, sex, ethnicity, and study characteristics.
Six of the reviewed studies were from the United States or Europe, and 13 were from Asia. The prevalence of prehypertension among participants ranged from 25.2% to 54.2%, and the duration of follow-up ranged from four to 36 years. Three studies included only women.
The researchers found that prehypertension increased the risk of stroke (RR, 1.66), compared with the optimal blood pressure of less than 120/80 mm Hg. Secondary outcome analyses revealed that low-range prehypertension increased the risk of stroke (RR, 1.44), and the risk was greater for high-range prehypertension (RR, 1.95).
“Our results are supported by a meta-analysis recently published by our group, showing that even low-range prehypertension increased the risk of cardiovascular disease compared with optimal blood pressure, and the risk was higher in individuals with high-range prehypertension,” stated the investigators.
The researchers also noted that their findings “reaffirm the importance of the definition of ‘prehypertension’ rather than being ‘normal’ for individuals with blood pressure of 120–139/80–89 mm Hg.” Hypertension is defined as a blood pressure greater than or equal to 140/90 mm Hg.
“Considering the high incidence of prehypertension, up to 30%–50%, successful intervention in this large population could have a major public health impact,” stated Dr. Huang’s group. “Many placebo-controlled trials have been performed in cohorts with prehypertensive average blood pressure levels for the treatment of other conditions (eg, treatment of atherosclerosis and prevention of diabetes), and a meta-analysis of these studies showed that the risk of stroke was significantly decreased by antihypertensive therapy in individuals with prehypertension.”
The researchers advised health care professionals to recommend lifestyle changes to their patients who have prehypertension. “High-risk subpopulations with prehypertension, especially individuals with high-range prehypertension combined with other cardiovascular risk factors, should be considered for future controlled trials of pharmacologic treatment to prevent stroke,” concluded Dr. Huang.
—Colby Stong