Objective There is ongoing controversy regarding a ‘J-curve’ phenomenon such that low and high blood pressure (BP) levels are associated with increased risks of recurrent stroke. We aimed to determine whether large treatment-related BP reductions are associated with increased risks of recurrent stroke.

Design Data are from the PROGRESS trial, where 6105 patients with cerebrovascular disease were randomly assigned to either active treatment (perindopril±indapamide) or placebo(s). There were no BP criteria for entry. BP was measured at every visit, and participant groups defined by reduction in systolic BP (SBP) from baseline were used for the analyses. Outcome was recurrent stroke.

Results During a mean follow-up of 3.9 years, 727 recurrent strokes were observed. There were clear associations between the magnitude of SBP reduction and the risk of recurrent stroke. After adjustment for cardiovascular risk factors and randomised treatment, annual incidence was 2.08%, 2.10%, 2.31% and 2.96% for participant groups defined by SBP reductions of ≥20, 10–19, 0–9 and <0 mm Hg, respectively (p=0.0006 for trend).

Conclusions The present analysis provided no evidence of an increase in recurrent stroke associated with larger reductions in SBP produced by treatment among patients with cerebrovascular disease.