Reconsidering the cut-off diastolic blood pressure for predicting cardiovascular events: a nationwide population-based study from Korea

Abstract

Aims It is unclear whether a J-curve association exists in cardiovascular risk prediction and how independently systolic and diastolic blood pressure (BP) predict cardiovascular outcomes. This study evaluated the association of systolic and diastolic BP with major cardiovascular events to clarify these issues. Methods and results Antihypertensive medication-naive subjects with available BP measurements and no history of cardiovascular events were extracted from the National Health Insurance Services Health Screening Cohort. The study endpoint was a composite of cardiac death, myocardial infarction, stroke, and heart failure. The study population comprised 290600 subjects (median follow-up duration 6.7years). The risk for major cardiovascular events was lowest at systolic and diastolic BPs of 90-99mmHg and 40-49mmHg, respectively, above which BPs demonstrated a log-linear risk prediction. Systolic and diastolic BPs were highly correlated. The risk prediction of diastolic BP was inconsistent when stratified by systolic BP. A wider pulse pressure rather than a higher diastolic BP was significantly associated with cardiovascular outcomes among men aged 55years. In addition, the difference between diastolic BPs of <80mmHg and 80-89mmHg mostly disappeared after statistical adjustment or stratification. Conclusion Elevated BP is a strong predictor of future cardiovascular events including cardiac death, myocardial infarction, stroke, and heart failure. This study showed that the log-linear relationship between BP and cardiovascular events extended down to a BP of 90/40mmHg. Although hypertension is defined using a lower systolic BP cut-off of 130mmHg, the diastolic BP component of 80mmHg seems disproportionately low.