The "J curve" problem revisited: old and new findings.

This paper critically addresses the issue of the "J-curve" paradox--the finding described in studies performed about 30 years ago indicating that treatment-induced systolic blood pressure values below 120 or 125 mm Hg and diastolic blood pressure values below 75 mm Hg are characterized by an increase, rather than a reduction, in the incidence of coronary events. This paper focuses on four major subjects: 1) the benefits of a lower blood pressure target during treatment; 2) the historical background of the "J-curve" phenomenon; 3) the evidence collected in recent clinical trials regarding the existence of a "J-curve" in treated hypertensive patients; and 4) the recent recommendations by the Task Force Committee of the European Society of Hypertension on blood pressure goals to be achieved during treatment.