Effects of blood pressure levels on case fatality after acute stroke

Abstract

Objective: We evaluated the relationship between admission blood pressure (BP) and early prognosis in patients with acute stroke in a single cohort.

Design: The subjects comprised 1004 cases of brain infarction and 1097 cases of brain hemorrhage, who were admitted to hospitals on the day of stroke onset. Death within 30 days after onset was evaluated in relation to admission BP levels.

Results: In brain infarction, a U-shaped relationship was found between BP levels and mortality rate, with a nadir at systolic blood pressure (SBP) of 150-169 mmHg and at diastolic blood pressure (DBP) of 100-110 mmHg. After adjustments for age and sex, the highest relative risks (RR) was observed in the lowest BP levels compared with nadir groups, and were 2.69 [95% confidence interval (CI), 1.43-5.07] in SBP and 3.49 (95% CI, 1.58-7.74) in DBP. In subjects with previous hypertension, the relationship between prognosis and SBP level shifted significantly toward higher pressure by about 10 mmHg compared with those without previous hypertension. In subjects with brain hemorrhage, the relationship between BP levels and mortality rate showed a J-shape in SBP and a U-shape in DBP. Highest BP levels had the poorest prognoses (>/= 230 mmHg in SBP, RR = 4.13, 95% CI = 2.45-6.94; >/= 120 mmHg in DBP, RR = 1.83, 95% CI = 1.11-3.04).

Conclusion: Lower and higher BP after brain infarction and higher BP after brain hemorrhage were predictors for poor early prognosis. In subjects with brain infarction, patients with previous hypertension had better outcomes at higher admission BP level than did normotensive patients.