Inflammation and Nocturnal Pattern of Blood Pressure in Normotensives

ABSTRACT

Abstract Background: In most healthy individuals, blood pressure (BP) shows a circadian rhythm. Being non-dipper increases cardiovascular risk in normotensive and hypertensive individuals. Nocturnal dipping shows a correlation with the state of inflammation. Objetive: To investigate the relationship between inflammation-based indexes and nocturnal BP pattern in normotensive individuals. Method: This is a retrospective study that included patients evaluated with ambulatory BP monitoring (ABPM). A total of 131 normotensive individuals were included and grouped as dippers and non-dippers. The normality of the data was verified with a Shapiro-Wilk test. We compared ABPM variables and inflammation-based indexes derived from blood tests (monocyte to high-density lipoprotein ratio [MHR], platelet to lymphocyte ratio [PLR], neutrophil to lymphocyte ratio [NLR], and systemic immune-inflammation index [SII]) between groups. The independent samples t-test and Mann-Whitney U test were used for comparing variables with normal and non-normal distributions, respectively. The Pearson's chi-squared test was used to compare categorical variables, and Spearman's correlation coefficient was used to examine the relationships between variables. A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic performances of inflammation-based indexes. The level of statistical significance was 5%. Results: The study included 131 patients (mean±standard deviation [SD] age 49.2±15.1 years, 58 [76.0%] of which were women). SII was significantly higher in the non-dipper group (p=0.033). Significant negative correlations were observed between the change in systolic BP [ΔSBP] and SII (r=-0.172, p=0.049) and between ΔSBP and PLR (r=-0.179, p=0.040). Conclusion: SII is a predictor of nocturnal BP pattern in normotensives.