A likely explanation for the J-curve of blood pressure cardiovascular risk

Area of Science:

• Cardiology
• Epidemiology
• Public Health

Background:

• Cardiovascular disease (CVD) remains a leading cause of mortality worldwide.
• Understanding the complex interplay between systolic and diastolic blood pressure (BP) is crucial for accurate risk stratification.
• Previous studies have suggested a J-curve relationship between diastolic BP and CVD, but the role of concomitant systolic BP requires further elucidation.

Purpose of the Study:

• To investigate the hypothesis that increased CVD incidence at low diastolic BP is primarily associated with elevated systolic BP, indicating increased pulse pressure.
• To examine the 10-year risk of nonfatal CVD events and CVD deaths across different diastolic BP categories stratified by systolic BP levels.

Main Methods:

• Prospective cohort study utilizing the combined original and offspring Framingham cohorts.
• Analysis of 951 nonfatal CVD events and 204 CVD deaths.
• Risk estimation at diastolic BP levels of <80, 80-90, and ≥90 mm Hg, categorized by concurrent systolic BP.

Main Results:

• A J-curve relationship between CVD incidence and diastolic BP was observed, becoming more pronounced with increasing systolic BP.
• A statistically significant excess of CVD events at diastolic BP <80 mm Hg was identified exclusively in individuals with systolic BP >140 mm Hg.
• This association remained significant after adjusting for age and other cardiovascular risk factors.

Conclusions:

• The increased risk of cardiovascular disease at low diastolic blood pressure is largely confined to individuals with elevated systolic blood pressure.
• Isolated systolic hypertension, characterized by low diastolic BP and high systolic BP, is a significant risk factor for CVD events.
• These findings underscore the importance of considering pulse pressure in CVD risk assessment and highlight the potential benefit of antihypertensive treatment in patients with isolated systolic hypertension.