Hypertension
Blood Pressure Lowering for the Prevention of Stroke Recurrence
Zengwu Wang,1
Tom Richart,2,3 Yu Jin,2 Jan A Staessen2,3 and Lisheng Liu1
1. Division of Hypertension, Fu Wai Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing; 2. Studies Co-ordinating Centre, Division of Hypertension and Cardiovascular Rehabilitation,
Department of Cardiovascular Diseases, University of Leuven; 3. Department of Epidemiology, Maastricht University
Abstract
Stroke is the second most common cause of mortality worldwide. It is the complication of hypertension that has the most direct link to blood pressure. Hypertension affects nearly 30% of the world’s population. In addition to hypertension, a previous history of cerebrovascular disease is a powerful predictor of stroke recurrence. In a meta-analysis of 10 trials of patients with previous cerebrovascular disease, blood- pressure-lowering treatment reduced systolic blood pressure (∆SBP) by 5.1mmHg and the risk of stroke recurrence by 22% (p=0.0007) compared with no treatment or placebo. In four trials involving diuretics as a component of therapy (∆SBP 9.6mmHg), the pooled reduction of stroke recurrence averaged 37% (p<0.0001), whereas it was only 7% in six trials of renin system inhibitors (∆SBP 4.0mmHg). In meta- regression analysis, the weighted correlation co-efficient between the odds for stroke recurrence and the blood pressure reduction was -0.57 (p=0.067). The significant heterogeneity (p<0.0001) between diuretics and renin system inhibitors in the prevention of stroke recurrence might be explained by the greater blood pressure reduction of treatments including diuretics. Our results do not support the use of renin system inhibitors for the prevention of stroke recurrence.
Keywords
Blood pressure lowering, stroke prevention, hypertension, eprosartan, nitrendipine, MOSES study
jan.staessen@med.kuleuven.beja.staessen@epid.unimaas.nl
Stroke is the second most common cause of mortality worldwide.1 Cerebrovascular disease caused an estimated 5.7 million deaths in 2005, with 87% occurring in low- or middle-income countries.2
Without
intervention, the global number of stroke deaths will rise to 6.5 million in 2015 and 7.8 million in 2030.2
Blood pressure is the most consistent and
powerful predictor of stroke. Hypertension affects nearly 30% of the world’s population.3,4 those in hypertension.5,6
Population mortality trends for stroke parallel In addition to hypertension, a previous history
of cerebrovascular disease is a powerful predictor of stroke recurrence.1 The purpose of our review was to summarise the evidence in favour of blood pressure lowering for the prevention of stroke recurrence.
Search Strategy
We identified original research papers on the prevention of stroke recurrence by systematically searching the table of contents (January 2000 until January 2009) of general interest and speciality journals that publish clinical research on hypertension or cerebrovascular disease. We searched the PubMed database (www.ncbi.nlm.nih.gov/sites/ entrez) for publications in English or with English abstracts. Starting from the preview/index tab, we chose the following as search terms for titles and abstracts: blood pressure, hypertension, stroke, haemorrhagic stroke, ischaemic stroke, recurrent stroke or any combination of these index terms. We also checked the reference lists of review papers for updates of clinical trials.
© T O UCH BRIEFINGS 2010
Active Treatment Compared with Placebo or No Treatment
As reported in detail elsewhere,7
10 randomised controlled trials8–17
investigated the effects of antihypertensive drug treatment versus no treatment or placebo on recurrent stroke in hypertensive or normotensive patients with a history of cerebrovascular disease. We extracted the characteristics of the 10 trials and those of the enrolled patients with a history of stroke from specific publications on stroke recurrence8–17 or from articles describing the baseline data18
or main results19,20 the reviewed trials. We combined the results of the 10 trials8–17 of on the
secondary prevention of stroke (11 groups of randomised patients) in stratified 2x2 tables. We computed pooled odds ratios from fixed effect models or, in the case of significant heterogeneity, from random effect models. In subgroup analysis, we contrasted trials that used a diuretic9–11,14
as opposed to renin system inhibitors8,12–16 as the mainstay of
active treatment. Renin system inhibitors, in addition to angiotensin- converting enzyme inhibitors and angiotensin II type 1 receptor blockers, also included β-blockers.21,22
We used the PROC MIXED procedure
as implemented in the SAS package, version 9.1.3 (SAS Institute, Carey, NC, US). We weighted pooled estimates of the odds ratios by the inverse of the variance of the odds ratios in individual studies and pooled estimates of the gradients in blood pressure by the number of patients randomised in each trial. We computed the weighted correlation between the odds of stroke recurrence on active treatment and the gradient
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