Both a retrospective and a prospective study of hypertensive patients have detected a significant positive relationship between pretreatment renin and sodium profiles, and the occurrence of coronary artery disease events during treatment. The subgroup of patients with the highest renin-sodium profile, while controlling for other known coronary risk factors as well as pre-existing disease, were significantly more likely to experience a fatal or nonfatal myocardial infarction compared with those with normal or low renin-sodium profiles. A population of almost entirely normotensive subjects failed to show a similar relationship for plasma renin activity alone. In the normotensive patient in whom the plasma renin activity is physiologically linked to blood pressure level, no adverse effect of an elevated plasma renin activity is seen. By contrast, in the hypertensive patient, in whom plasma renin activity should approach zero, there is a direct correlation between the renin-sodium profile and the risk of developing subsequent heart attack.