The J-curve phenomenon in stroke recurrence.

BACKGROUND AND PURPOSE: The relation of poststroke blood pressure to stroke recurrence remains undetermined, and the optimal control of blood pressure has not been established. We performed the present study to resolve these issues. METHODS: We analyzed 368 stroke patients with a history of hypertension (mean age, 62 years) who were admitted within 3 months after stroke onset and observed for 6 months or more. We determined stroke recurrence rate in relation to baseline (or initial) blood pressure, mean values of poststroke blood pressure, stroke subtypes, age, antihypertensive treatment, and other clinical features. RESULTS: The recurrence rate had a J-curve relation to poststroke diastolic blood pressure but not to poststroke systolic blood pressure and baseline diastolic and systolic blood pressures. The stroke recurrence rate was 3.8% per patient-year in 94 patients who had a poststroke diastolic blood pressure of 80 to 84 mm Hg, significantly lower than the rates of 9.2% per patient-year (P < .05) and 11.4% per patient-year (P < .01) in those with a lower and higher poststroke diastolic blood pressure, respectively. The range of poststroke diastolic blood pressure accompanying the lowest stroke recurrence rate was higher in patients with atherothrombotic (85 to 89 mm Hg) than in those with lacunar infarction (80 to 84 mm Hg). Neither antihypertensive therapy nor patients' age affected this phenomenon. CONCLUSIONS: The present study suggests that lower blood pressure does not always result in favorable effects on stroke recurrence. The effects of poststroke blood pressure and antihypertensive therapy on stroke recurrence may be complicated by the J-curve phenomenon.