Lowering blood pressure after stroke reduces the risk of recurrent stroke and other vascular events. However, there is recent evidence that low blood pressure may also result in poor outcome. For the first time, this study aimed to investigate the relationship between blood pressure and outcome in long-term survivors of stroke.
Participants from the North East Melbourne Stroke Incidence Study were contacted at 5 years after stroke for a follow-up assessment. Blood pressure was measured according to a strict protocol. A multivariable Cox proportional hazards regression model was used to assess the association between SBP measurements at 5 years after stroke and outcome (death, acute myocardial infarction or recurrent stroke) to 10 years after stroke.
In 5-year survivors of stroke, compared to a SBP of 131–141 mmHg, a SBP of 120 mmHg or less was associated with a 61% greater risk of stroke, acute myocardial infarction and death (hazard ratio 1.61, 95% confidence interval 1.08–2.41, P = 0.019). Compared to the reference category of SBP 131–141 mmHg, there were no differences in outcome in the patients with SBP 121–130 mmHg (P = 0.491) or 142–210 mmHg (P = 0.313). These findings were not modified when adjusting for prescription of antihypertensive medications.
There was a greater risk of poor outcome in long-term survivors of stroke with low SBP. This is further evidence that low SBP may result in poor prognosis. Ideal blood pressure levels for long-term survivors of stroke may need to be reassessed.