Factors determining sodium chloride sensitivity of patients with essential hypertension: evaluation by multivariate analysis

Factors which determine sodium chloride sensitivity, defined as the difference between the mean blood pressure after 1 week of a low sodium chloride diet (3 g/day) and that after 1 week of a high sodium chloride diet (20 g/day), were studied in 60 inpatients with essential hypertension using a multivariate analysis. The sodium chloride sensitivity was independently correlated with the change in erythrocyte sodium concentration (r = 0.47) and with the change in plasma renin activity (r = 0.29); but it was not related to basal blood pressure, the change in plasma volume of the change in plasma norepinephrine concentration. These data suggest that both intracellular sodium accumulation and inadequate suppression of the renin-angiotensin system may be independently involved in the elevation of blood pressure after sodium chloride loading. We could not find the independent importance of volume retention, hyperadrenergic activity or basal blood pressure in the sodium chloride sensitivity.