Renin and age as determinants of a predominantly betablocker-based antihypertensive drug program.

Patients with essential hypertension can be subdivided into groups with low (19%), normal (59%) or high (23%) renin sodium index. The proportion with low renin hypertension increases with age. Patients with high renin fall in two categories: younger patients with fairly mild hypertension and older patients with more severe hypertension and signs of renal disease. The antihypertensive efficacy of betablocker monotherapy is best in high renin forms, good but less consistent in normal renin patients and uniformly bad in low renin hypertensives. In relation to age, betablockers normalized blood pressure (less than or equal to 95 mm Hg diastolic) in three-quarters of the younger-than-40-year-olds, in about half of those 40-60 years of age but in only 20% of those over 60 years. On this basis, it is postulated that the older patients with a low renin exhibit a relatively hypoadrenergic state whereas those with a normal or high renin--for a given age and elevated pressure--have a relatively increased adrenergic nervous activity. Because the betablockers have a potent suppressive action on the renin-angiotensin system--and, as a consequence, on angiotensin vasoconstriction, aldosterone volume expansion and central stimulatory feedback mechanisms--their antihypertensive mode of action may be linked to an important extent, although not exclusively, to renin suppression.