The salivary sodium/potassium ratio in hypertension: relation to race and plasma renin activity.

We have studied the relationship between plasma renin activity (PRA) and the salivary Na:K ratio, an index of mineralocorticoid effect, in 223 patients with essential hypertension. In 24 white patients with low PRA the median Na:K ratio was 0.74, which was significantly lower than the ratio of 1.40 in 54 normal white subjects (P less than .005) and the ratio of 1.10 in 34 white hypertensive patients with normal PRA (P less than .005). The Na:K ratio in 71 black patients with low PRA was 1.06, which was not significantly lower than the ratio of 1.50 in 38 black normal subjects or the ratio of 1.56 in 94 black hypertensive patients with normal PRA. These findings indicate a difference in salivary Na:K ratios between white and black patients with low renin essential hypertension, and suggest that mineralocorticoid excess may be a more frequent cause of low renin essential hypertension in white than in black patients.