Association between within-visit blood pressure variability, stroke, coronary heart disease, and cardiovascular mortality.

ABSTRACT

INTRODUCTION: Long-term variability in systolic blood pressure (SBP) is associated with a higher risk of cardiovascular events. Little is known about any association between within-visit SBP variability, stroke, coronary heart disease (CHD), and cardiovascular (CV) death. MATERIAL AND METHODS: Participants included adults ≥ 18 years who participated in the US National Health and Nutrition Examination Surveys from 1999 to 2012 linked to the national death index in 2012. Stroke was self-reported. SBP was obtained up to four times by a physician, using a manual sphygmomanometer according to standard procedures. Within-visit SBP variability was defined as the standard deviation of the BP measurements, stratified into quartiles. We evaluated the relationship between within-visit SBP variability and the odds of stroke or CHD using multivariable logistic regression, and with CV mortality, using multivariable Cox regression. RESULTS: Of the 27,987 adults, 16.4% were aged ≥ 65 years, 51.3% were female, 71.2% were white, and 10.7% were black. Factors associated with higher mean SBP variability included older age, hypertension, chronic kidney disease, peripheral artery disease, and smoking (all p < 0.05). The prevalence of stroke significantly increased across SBP variability quartiles, from 2.1% for quartile 1 to 3.7% for quartile 4 (p < 0.001). High SBP variability was associated with higher odds of stroke [odds ratio (OR) 1.8, 95% confidence interval (CI) 1.4-2.2], coronary heart disease (OR 2.0, 95% CI 1.6-2.4), and increased risk of CV mortality [hazard ratio (HR) 2.7, 95% CI 2.3-3.1]. The relationships were not observed after adjusting for covariables. CONCLUSIONS: Within-visit variability in SBP is associated with increased risks of stroke, coronary heart disease, and cardiovascular mortality, but the relationship is confounded by age and covariates.