The J-shaped Curve for Blood Pressure and Cardiovascular Disease Risk: Historical Context and Recent Updates

The definition and treatment of hypertension have both changed dramatically over the last century, with recent trials suggesting benefit for lower blood pressure (BP) targets than ever before considered. However, tempering the enthusiasm for more intensive BP targets are long-held concerns that BP reduction below a certain threshold may pose dangers, the so-called "J-curve." In this review, we summarize the evidence for a J-curve in the treatment of hypertension.

The Systolic Blood Pressure Intervention Trial (SPRINT) reported that achieving a systolic BP target of 120 mmHg reduces cardiovascular disease in high-risk individuals, supporting more intensive BP reduction. However, contemporary observational studies consistently demonstrate a BP J-curve, the threshold of which is often close to the SPRINT target. Studies also suggest that the BP level of this J-curve may vary based on patient characteristics, including age and comorbidities. There is also more compelling evidence for the specific presence of a J-curve between diastolic BP and coronary events, in contrast to conflicting evidence of a J-curve with systolic BP and cardiovascular disease more generally. There is increased risk of coronary events below a diastolic BP of 60-70 mmHg. In comparison, the presence of a systolic J-curve is less clear and some persons at high risk may actually benefit from systolic levels down to 120 mmHg. Therefore, we suggest a personalized approach to BP management considering individual risks, benefits, and preferences when choosing therapeutic targets. Further, well-designed studies are required to support our suggestions and to define J-curve thresholds more clearly.