Association between B-type natriuretic peptide and within-visit blood pressure variability.

Background: Blood pressure variability (BPV) has been shown to predict cardiovascular events. Within-visit BPV is the simplest and easiest measure of BPV, but previous studies have shown conflicts as to whether within-visit BPV correlates with target organ damage. We aimed to evaluate whether within-visit BPV correlates with B-type natriuretic peptide (BNP) in a general population.

Hypothesis: Within-visit BPV correlates with BNP in a general population.

Methods: This was a cross-sectional study that included 633 individuals, randomly selected, age 45 to 99 years, registered in the primary care program from an urban medium-sized town. Patients were scheduled for a single-day visit that consisted of clinical evaluation and laboratory tests. Three blood pressure (BP) readings, 1 minute apart, were done, and within-visit BPV was determined as the coefficient of variation (CV) of the 3 BP measures. Our main outcome was to correlate BNP and within-visit BPV. A multivariable model was estimated using a generalized linear model to evaluate the independent effects of different variables on BNP levels.

Results: The median age was 57 years. Median BNP was 16 pg/mL, and the median systolic and diastolic BP-CV were, respectively, 3.9% and 3.5%. There was a weak but positive correlation between BNP and both systolic BP-CV and diastolic BP-CV (r = 0.107 and P = 0.007 and r = 0.092 and P = 0.019, respectively). In multiple regression equation, systolic BP, diastolic BP-CV, body mass index, and estimated glomerular filtration rate were associated with BNP.

Conclusions: In the present study, there was a positive, albeit weak, correlation between within-visit BPV and BNP. In addition, diastolic BPV was associated with BNP even after adjustment for multiple confounders.