Eight randomised controlled trials (29,667 patients, range 194 to 20,332) were included in the review. Five studies were allocated Jadad scores of five points, one study was given a score of four points and two studies received Jadad scores of three points.
Treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers was associated with statistically significant reductions of the risk of future major vascular events (RR 0.91, 95% CI 0.87 to 0.97; seven trials; Ι²=61%) and recurrent stroke (RR 0.93, 95% CI 0.86 to 0.99; eight trials; Ι²=6%). Exclusion of the smallest study from the analysis of future major vascular events continued to show a significant result indicating benefits of the intervention (RR 0.92, 95% CI 0.87 to 0.97), but statistical heterogeneity was not significant (Ι²=41%). A borderline significant benefit was also observed with renin-angiotensin system modulators compared to calcium channel blockers in reducing the risk of major vascular events (RR 0.89, 95% CI 0.80 to 1.00, three trials; Ι²=58%), but there were no differences between the interventions and calcium channel blockers for recurrent strokes.
Treatment with renin-angiotensin system modulators was associated with a statistically significant higher risk of hypotension (RR 1.87, 95% CI 1.61 to 2.17; two trials). There were no significant differences between treatment groups angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and the comparator groups in major coronary events (five trials), death from cardiovascular causes (one trial) and total death (two trials).
The results of the subgroup analyses showed similar patterns of results to the main findings for the primary outcomes of risk of major vascular events and recurrent stroke.
The results from the visual appraisals of the funnel plots showed no evidence of publication bias.