How Systolic, Diastolic Blood Pressure Impact CVD Outcomes

Regardless of the definition of hypertension, recent study findings show that systolic and diastolic hypertension independently impact the risk of adverse cardiovascular events, but systolic blood pressure elevation has a greater effect on outcomes. These findings were published online in the New England Journal of Medicine.  

“The relationship between outpatient systolic and diastolic blood pressure and cardiovascular outcomes remains unclear and has been complicated by recently revised guidelines with two different thresholds (≥140/90 mm Hg and ≥130/80 mm Hg) for treating hypertension,” explained Alexander C Flint, MD, PhD, Kaiser Permanente, and colleagues.  

For the study, the research team used data from 1.3 million adults in a general outpatient population. To determine the effect of the burden of systolic and diastolic hypertension on composite outcome of myocardial infarction, ischemic stroke, or hemorrhagic stroke over an 8-year period, the researchers performed a multivariable Cox survival analysis. They noted that the analysis controlled for both demographic characteristics as well as coexisting conditions.  

“The burdens of systolic and diastolic hypertension each independently predicted adverse outcomes,” the researchers said based on the findings.

According to study outcomes, the researchers observed a continuous burden of systolic hypertension (≥140 mm Hg; hazard ratio per unit increase in z score, 1.18; 95% confidence interval [CI], 1.17 to 1.18) and diastolic hypertension (≥90 mm Hg; hazard ratio per unit increase in z score, 1.06; 95% CI, 1.06 to 1.07) independently predicted the composite outcome. 

“Similar results were observed with the lower threshold of hypertension (≥130/80 mm Hg) and with systolic and diastolic blood pressures used as predictors without hypertension thresholds.” 

The researchers noted that there was a “J-curve relation” between diastolic blood pressure and outcomes. According to the study authors, this was due in part to age and other covariates and by a higher effect of systolic hypertension among persons in the lowest quartile of diastolic blood pressure. 

“Although systolic blood-pressure elevation had a greater effect on outcomes, both systolic and diastolic hypertension independently influenced the risk of adverse cardiovascular events, regardless of the definition of hypertension (≥140/90 mm Hg or ≥130/80 mm Hg),” Dr Flint and colleagues concluded.

—Julie Gould  

Reference:

Flint AC, Conell C, Ren X, et al. Effect of systolic and diastolic blood pressure on cardiovascular outcomes [published online July 18, 2019]. N Engl J Med. 2019; 381:243-251 doi: 10.1056/NEJMoa1803180