Body fluid compartments in hypertension

Background and objectives: There is a correlation between the fluid and ionic homeostasis and blood pressure but it is not known if these body fluid changes represent the cause or rather the effect of the blood pressure rise. We have estimated the compartmental distribution of body fluids by means of the Bioimpedance Spectroscopy (BIS) analysis in a hypertensive cohort compared to control subjects. Material and methods: We have enrolled 28 hypertensive patients (14 females, 14 males, mean age 47 ± 5) and a sex- and age-matched control group of 37 healthy subjects (17 females and 20 males, mean age 45 ± 8). They underwent anthropometric measurements, then extracellular (ECW) and intracellular water (ICW) were assessed using BIS. Results: Both mean weight and BMI of hypertensive patients resulted significantly higher than of the control group (p < 0.05). We found higher ICW values in hypertensive compared to normotensive subjects. This difference was proportional to the difference of mean blood pressure values, reaching significance only as regards the stage II hypertensive subgroup (p < 0.03). Discussion: Our data confirm that the blood pressure increases are associated to TBW, and caused mainly by ICW increases. The BIS, a simple, reliable, non invasive and cost effective methodical approach, estimating the distribution of body fluids, offers now possibility of the management of the hypertensive disease, to establish a more appropriate antihypertensive treatment. Moreover, the BIS, estimating the volume restoration of the different body compartments, may be helpful in evaluating the effectiveness of the pharmacological treatment.