High within-visit systolic blood pressure variability is associated with stroke and diabetes
Authors: Visaria A D , Kostis J B , Kostis W J 
Published: October 2021

Abstract

Background
Within-visit systolic blood pressure variability (SBPV) has been inconsistently, positively associated with cardiovascular (CVD) outcomes.

Purpose
We sought to determine whether SBPV was cross-sectionally associated with CVD and CVD risk factors in a nationally representative study population of United States adults.

Methods
Using the 2011–2018 National Health and Nutrition Examination Surveys, a total of 10,879 adults ≥20 years not taking antihypertensive medications were included. After an initial five-minute rest, participants had three, sitting, consecutive BP readings (30 sec. rest in between) taken by protocol-trained physicians using a mercury sphygmomanometer. SBPV was calculated as 1) the standard deviation (SD) of the three BP readings and categorized into less than, and greater than or equal to the 75th percentile (SD≥4.2 mmHg). We also calculated the maximum minus minimum SBP difference (MMD), categorized into less than 10, and greater than or equal to 10 mmHg. The primary outcomes were self-reported history of CVD outcomes, including stroke, myocardial infarction, coronary heart disease, and heart failure. Secondary outcomes included increased waist circumference, impaired glucose tolerance, diabetes, hypertriglyceridemia, and low HDL. We used one-way ANOVA, chi-square tests, and multivariable logistic regression to determine association between SBPV and CVD outcomes. All analyses accounted for the complex survey design and had a significance level of 0.05.

Results
Among the 10,879 participants, 2,386 (20%) had high SBPV. Those with high SBPV were older (mean [SD]; 47.0 [0.6] vs. 41.8 [0.3], p&lt;0.0001), had higher mean SBP (mean [SD] mmHg; 121 [0.4] vs. 118 [0.2], p&lt;0.0001), higher max SBP (127 [0.4] vs. 120 [0.2], p&lt;0.0001), higher HbA1c % (5.54 [0.02] vs. 5.48 [0.01]) but similar lipid profiles. Accordingly, high SBPV participants were more likely to have diabetes, but had no difference in other metabolic syndrome criteria (Figure 1). High SBPV participants were more likely to have a history of stroke (1.7% vs. 0.8%, p&lt;0.0001), but less likely to have myocardial infarction (p=0.028; Figure 2). After adjustment for covariates, those with high SBPV had 50% higher odds of stroke compared to those without high SBPV (OR [95% CI]; 1.50 [1.11, 2.03]). This association persisted when using MMD (1.48 [1.04, 2.11]). However, the adjusted associations were attenuated when treating SBPV as a continuous variable (SD, unadjusted OR [95% CI]: 1.14 [1.07, 1.21], adjusted OR: 1.06 [0.99, 1.13]).

Conclusion
Participants with high SBPV were more likely to have diabetes and history of stroke. SBPV greater than or equal to 4.2 mmHg or maximum-minus-minimum SBP difference greater than or equal to 10 mmHg both were associated with nearly 50% higher odds of stroke. This suggests that stroke survivors may benefit from interventions to decrease within-visit BP variability to improve BP measurement accuracy and potentially prognosis.

Funding Acknowledgement
Type of funding sources: None. Figure 1. Cardiometabolic Factors & BPVFigure 2. Cardiovascular Disease & BPV