Low Renin Hypertension - Is It a Stage of Essential Hypertension?

Abstract

Resting plasma renin activity (PRA) and PRA after the load of furosemide i. v. and two-hour's upright posture were studied on 139 healthy normotensive subjects and 200 patients with essential hypertension. Regarding the age factor, the estimated values in control subjects were very low in the advanced ages over 60 years, while no significant differences were found in the subjects aged from 20 to 59 years. In essential hypertension, a similar relationship between renin and aging was observed. The patients with essential hypertension were classified into 3 groups according to the resting PRA values; low, normal and high. There were no signi-ficant differences among the. 3 groups concerning the mean ages and the blood pressure. Regarding the incidence of low PRA hypertension at different ages there were no significant differences among the decades ander 60 years of age. On the other hand, all hypertensive patients were classified into 3 groups according to their responses of renin secretion; low responders, normal responders, and high res-ponders. There was a positive correlation between the incidences of hyporesponders of renin secretion and the age. Higher incidences of hyporesponders were obtained in older patients. The incidence of hyperresponders was higher in younger patients than in older patients. Our study revealed that the incidences of low resting PRA were similar in each decade under 60 years, and it seems unlikely that low renin hypertension is a stage in a long-term course of essential hypertension. On the contrary, the hyporesponders of renin secretion to the load are apparently related to the age. It is concluded that low PRA essential hypertension must be distinct from the hyporesponder of renin secretion.