STABILITY – Hypertension Trial

Visit-to-visit variability of blood pressure and cardiovascular outcomes in patients with stable coronary heart disease. Insights from the STABILITY trial
European Heart Journal (2017)  doi:10.1093/eurheartj/ehx250

Objective:  To study the relation between visit-to-visit variability of blood pressure (BP) and long term cardiovascular risk in patients with stable coronary heart disease.

Methods:

  • STABILITY trial was a multicentre, double-blind, randomized clinical trial in which 15 828 patients with established CHD were followed up for 2.6 years
  • During the first year of the study, diastolic and systolic BP were measured at 5 visits (baseline, month 1, month 3, month 6, and month 12). Visit-to visit-variability was assessed from the
    standard deviation (SD) of BP across these 5 visits.
  • Patients who developed CV events within 1st year were excluded. Data was included from 13794 patients.
  • Primary Endpoint:  a composite of time to cardiovascular death, myocardial infarction, or stroke (Major Adverse Cardiovascular Event, MACE) occurring beyond the first 12months following randomization.

Results:

  •  13 794 patients were included in this study, Mean Age: 65 years, 78% patients had hypertension.
  • Mean average BP during the first year of study was 131/78.3  mmHg.
  • Mean of the visit-to-visit SD was 9.8 (4.8) mmHg for systolic and 6.3 (3.0)mmHg for diastolic BP.
  • patients were divided in 3 tertiles as per SD of Visit to visit BP variability .
  • After adjustment with other risk factors, the primary endpoint was associated with SD of systolic BP (hazard ratio for highest vs. lowest tertile, 1.30, 95% CI 1.10–1.53, P = 0.007, Figure A), and with SD of diastolic BP (hazard ratio for highest vs. lowest tertile, 1.38, 95% CI 1.18–1.62, P < 0.001, Figure B).

  • Each 5 mm Hg increase in Visit to visit BP variability increased risk of CV events significantly as following

    • MACE by 14%,
    • CV mortality by 15%,
    • MI (myocardial infarction) by 20% and
    • All cause mortality by 12% 

Conclusion:
In patients with stable coronary heart disease, higher visit-to-visit variabilities of both systolic and diastolic BP are
strong predictors of increased risk of cardiovascular events, independently of mean BP.