Systolic vs diastolic BP elevations: which matters more for CVD risk?

  • Flint AC & al.
  • N Engl J Med
  • 18 Jul 2019

  • International Clinical Digest
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Takeaway

  • Elevated systolic (SBP) and diastolic (DBP) blood pressure both contribute independently to cardiovascular disease (CVD) risk, although SBP has a greater effect. 

Why this matters

  • Conflicting hypertension thresholds and evidence base do not help resolve the question of whether SBP or DBP elevations matter most for CVD risk. 
  • In this study, the effects of both are present with the lower 2017 hypertension threshold of ≥130/80 mmHg and with the ≥140/90 mmHg threshold, supporting the proposed benefits of the 2017 guidelines change.

Key results

  • SBP and DBP (mmHg) hypertension independently predict adverse cardiovascular outcomes (adjusted HRs per unit z-score increase; 95% CIs):
    • SBP ≥140: 1.18 (1.17-1.18);
    • SBP ≥130: 1.18 (1.17-1.19);
    • DBP ≥90: 1.06 (1.06-1.07); and
    • DBP ≥80: 1.08 (1.06-1.09).
  • Increasing quantiles of SBP correlated with increased adverse outcome risks.
  • DBP showed a J-shaped curve, with highest risk for myocardial infarction or stroke in the lowest and highest deciles.
  • Isolated SBP and isolated DBP were also linked to increased CVD events.

Study design

  • Data from outpatient population of 1,316,363 adults with 36,784,850 BP measurements.
  • Primary composite outcome: first episode of myocardial infarction, stroke (ischemic/hemorrhagic).
  • Funding: Kaiser Permanente Northern California Community Benefit Program. 

Limitations

  • Retrospective study of prospectively built databases.
  • BP measures during routine visits.
  • Diet modifications not known.