THE IMPACT OF THE VISIT-TO-VISIT VARIABILITY OF BLOOD PRESSURE ON THE CARDIOVASCULAR OUTCOMES IN THE KOREAN NATIONAL HEALTH INSURANCE SERVICE - NATIONAL SAMPLE COHORT (NHIS-NSC)

Abstract

Objective: Despite an association between the visit-to-visit variability (VVV) of blood pressure (BP) and the cardiovascular (CV) outcomes, many studies performed during the past 4 years showed the conflicting results. The aim of this study was to investigate the impact of VVV on the CV outcomes in the Korean National Health Database cohort.

Design and Method: Among 2002 Korean National Health Database (n = 47,851,928), sampled 53,124 subjects with BP measurement over 3 times were divided into 2 groups, according to the cut-off value of 10 mmHg in visit-visit SD of SBP (VV-SD-SBP) and the CV outcomes were compared.

Results: In the Kaplan-Meier survival curve, subjects with the VV-SD-SBP ≥ 10 mmHg showed the lower rate of event-free survival rate. Irrespective of the sampling timing, subjects with the VV-SD-SBP ≥ 10 mmHg had higher rate of CV events or death, nonfatal MI or stroke and total mortality. However, higher VVV was not associated with CV mortality. In the Cox proportional hazard model, the hazard ratio for CV events or death was 1.48 (95% confidence interval [CI], 1.27 to 1.73, p < 0.0001), for nonfatal MI or stroke 1.48 (95% CI, 1.26 to1.74, p < 0.0001), for CV mortality 1.34 (95% CI, 0.82 to 2.20, p = 0.23), and for total mortality 1.35 (95% CI, 1.09 to 1.68, p = 0.0069), respectively.

Conclusions: In the representative sample of the general population in Korea largely including non-hypertensive subjects, on the basis of significant associations between the VV-SD-SBP and CV outcomes, increased VVV of SBP was an independent risk factor for CV outcomes, independently of mean BP status.