Blood pressure-lowering treatment for preventing recurrent stroke, major vascular events, and dementia in patients with a history of stroke or transient ischaemic attack.

Stroke is an important cause of death and disability worldwide. Since high blood pressure is an important risk factor for stroke and stroke recurrence, drugs that lower blood pressure might play an important role in secondary stroke prevention. To investigate whether blood pressure-lowering drugs (BPLDs) started at least 48 hours after the index event are effective for the prevention of recurrent stroke, major vascular events, and dementia in people with stroke or transient ischaemic attack (TIA). Secondary objectives were to identify subgroups of people in which BPLDs are effective, and to investigate the optimum systolic blood pressure target after stroke or TIA for preventing recurrent stroke, major vascular events, and dementia. In August 2017, we searched the Trials Registers of the Cochrane Stroke Group and the Cochrane Hypertension Group, the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 8), MEDLINE Ovid (1946 to August 2017), Embase Ovid (1974 to August 2017), ClinicalTrials.gov, the ISRCTN Registry, Stroke Trials Registry, Trials Central, and the World Health Organization (WHO) International Clinical Trials Registry Platform Portal. Randomised controlled trials (RCTs) of BPLDs started at least 48 hours after stroke or TIA. Two review authors independently screened all titles and abstracts, selected eligible trials, extracted the data, assessed risk of bias, and used GRADE to assess the quality of the evidence. If necessary, we contacted the principal investigators or corresponding authors for additional data. We included 11 studies involving a total of 38,742 participants: eight studies compared BPLDs versus placebo or no treatment (35,110 participants), and three studies compared different systolic blood pressure targets (3632 participants). The risk of bias varied greatly between included studies. The pooled risk ratios (RRs) of BPLDs were 0.81 (95% confidence interval (CI) 0.70 to 0.93; 8 RCTs; 35,110 participants; moderate-quality evidence), 0.90 (95% CI 0.78 to 1.04; 4 RCTs; 28,630 participants; high-quality evidence) for major vascular event, and 0.88 (95% CI 0.73 to 1.06; 2 RCTs; 6671 participants; high-quality evidence) for dementia. We mainly observed a reduced risk of recurrent stroke in the subgroup of participants using an angiotensin-converting enzyme (ACE) inhibitor or a diuretic (I2 statistic for subgroup differences 72.1%; P = 0.006). The pooled RRs of intensive blood pressure-lowering were 0.80 (95% CI 0.63 to 1.00) for recurrent stroke and 0.58 (95% CI 0.23 to 1.46) for major vascular event. Our results support the use of BPLDs in people with stroke or TIA for reducing the risk of recurrent stroke. Current evidence is primarily derived from trials studying an ACE inhibitor or a diuretic. No definite conclusions can be drawn from current evidence regarding an optimal systolic blood pressure target after stroke or TIA.