12 Mar Long-Term Risk of Stroke Raised by PreHypertension
MedicalResearch.com Interview with:
Dingli Xu, MD
From Department of Cardiology
Nanfang Hospital, Southern Medical University, Guangzhou, China
MedicalResearch.com: What are the main findings of the study?
Answer：Our study showed that after controlling for multiple cardiovascular risk factors, the blood pressure range at 120-139/80-89 mm Hg (defined as ‘prehypertension’ in JNC 7), is significant associated with long-term risk of stroke. The results were consistent across stroke type, stroke endpoint, age, study characteristics, follow-up duration, and ethnicity. More importantly, even low-range prehypertension (BP 120-129/80-84mmHg) increased the risk of stroke compared with optimal BP (<120/80 mm Hg), and the risk was higher in individuals with high-range prehypertension (BP 130-139/85-85mmHg). In particular, we found that compared with individuals with optimal blood pressure individuals with low-range prehypertension were 44% more likely to develop stroke, and this risk was even greater (95%) in individuals with high-range prehypertension.
MedicalResearch.com: Were any of the findings unexpected?
Answer: Yes, we believed that two findings are very interesting. First, prehypertension, which seemed “normal” in the past, is significant associated with risk of stroke, even after adjusted multiple cardiovascular risk factors. This means that the mild elevation of blood pressure could directly increases the risk of stroke.
Second, even low range prehypertension, which is defined as ‘normal blood pressure’ in some hypertension guideline, could also increase the risk of stroke significantly. This result is different with prior studies and meta analysis. Therefore, our findings reaffirms the importance of the definition of “prehypertension” rather than being “normal”.
MedicalResearch.com: What should clinicians and patients take away from your report?
Answer: These findings have important clinical and public health implications. First, clinicians and patients should be aware of that blood pressure range at 120-139/80-89mmHg is not “normal”. These individuals are at a high risk to progress to sustained hypertension, as well as CVD, especially stroke, so periodic screening is important. Second, considering the robust evidence of an association between prehypertension and the risk of stroke shown in our study, it is preferable to consider earlier interventions for prehypertension among the general population. Currently, lifestyle modification is the mainstay of treatment for prehypertension in the general population (e.g. quit smoking, increased physical activity, maintain proper body weight.). This should be recommended to every individuals with prehypertension.
However, because of the significant difference in the risk of stroke for BP between 120–129/80–84 mm Hg and 130–139/85–89 mm Hg, we suggest that, for clinicians, this category should be subdivided into low- and high-range prehypertension. Further studies are needed to reveal better predictors of high-risk subpopulations with prehypertension (especially in high-range prehypertension) to select subpopulations for future controlled trials of pharmacological treatment.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Answer: In our study, we found that prehypertension, even in the low range, elevates the risk of stroke after adjusting for multiple cardiovascular risk factors. However, whether treatment of prehypertension can reduces the risk of target organ damage is still with controversies. Based on the lack of prospective, randomized trials examining the effects of anti-hypertensive therapy on reducing target organ damage specifically in prehypertensives, professional societies do not recommend drug treatment in prehypertension, even in high-range prehypertension.
So we think that there is a great gap to be covered between epidemiological studies and randomized controlled studies in prehypertension. Prehypertensive individuals are at a high risk to progress to sustained hypertension, as well as CVD, especially stroke. So for therapeutic implications, we emphasize that lifestyle intervention, but not medical intervention is the mainstay of treatment for prehypertension. However, high-risk subpopulations with prehypertension are needed to be selected for future controlled trials of pharmacological treatment.