The diastolic blood pressure J-curve remains an observational research phenomenon that has not yet been proven as causal and should not be used to make invasive treatment decisions

The Diastolic Blood Pressure J-Curve in Hypertension Management: Links and Risk for Cardiovascular Disease

PURPOSE OF REVIEW

The treatment of hypertension has changed dramatically over the last century, with recent trials informing clinical guidelines that recommend aiming for lower blood pressure (BP) targets than ever before. However, a "J"- or "U-shaped curve" in the association between diastolic BP and cardiovascular events has been observed in epidemiological studies, suggesting that both high diastolic BPs and diastolic BPs below a certain nadir are associated with higher risk of cardiovascular disease (CVD) events. Despite the potential for confounding and reverse causation, this association may caution against overly intensive BP lowering in some hypertensive adults who also have a low baseline diastolic BP.

RECENT FINDINGS

Recent post-hoc analyses of the landmark Systolic Blood Pressure Intervention Trial (SPRINT) appear to contradict these J-curve concerns, finding that the benefit of more intensive BP treatment did not differ based on baseline blood pressure. Similarly, sensitivity analyses of The Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) randomized controlled trial found that patients experienced similar benefits from an intensive BP goal, regardless of whether their diastolic BP was above or below 60 mm Hg. Finally, several Mendelian randomization analyses, which are less susceptible to confounding and reverse causation, demonstrated a clear linear relationship between diastolic BP and cardiovascular events. These studies indicate that a potential reduction in CVD risk is possible, irrespective of baseline diastolic BP values.

SUMMARY

Sufficient recent evidence indicates that low diastolic BP is not causal of worse cardiovascular outcomes but rather represents confounding or reverse causation. Therefore, while low diastolic BP can be considered a marker of CVD risk, this risk is not expected to increase with further BP lowering when necessary to control concomitant elevations of systolic BP. Indeed, BP reduction in this setting appears beneficial.

Establishing target systolic and diastolic blood pressure in diabetic patients with hypertension: what do we need to consider?

INTRODUCTION

The optimum target for systolic and diastolic blood pressure remains divisive. In particular, the conflicting outcomes of the SPRINT and ACCORD trials have led to a divergence of guideline-recommended blood pressure targets for adults with diabetes.

AREAS COVERED

Here, we review the existing recommendations for blood pressure targets in diabetes, discussing the evidence base behind them and their limitations. We start by outlining the risks and benefits of lower systolic blood pressure targets among diabetics. We then follow with a separate appraisal of diastolic blood pressure targets, which necessitates examination of the 'J curve' and isolated diastolic hypertension.

EXPERT OPINION

Current and emerging evidence supports, on balance, a blood pressure therapeutic target of < 130/90 mmHg in adults at increased risk for cardiovascular disease, including diabetics. Whether certain diabetics with systolic BPs of 120-130 and/or diastolic BPs 80-90 mmHg require drug treatment to a target of <120/80 mmHg is less clear and requires more research.