Renin and beta-blockade: prorenin and aldosterone may explain the controversy

The role of the renin-aldosterone system in predicting the hypotensive effect of beta-blockade is controversial. We have measured blood pressure, heart rate, plasma active renin, prorenin and aldosterone in 44 hypertensive patients before and after 18 weeks treatment with either nadolol or metoprolol in a double blind randomized study. Prorenin increased and active renin decreased with treatment, total renin and aldosterone remaining unchanged. After beta-blockade the correlation between active renin and prorenin improved from p less than 0.025 to p less than 0.001, and both variables attained a correlation with aldosterone. There was a weak correlation between the reduction in diastolic pressure and both pretreatment active renin and pretreatment prorenin (p less than 0.05). However, using a multiple regression analysis there was a highly significant correlation between the combination of the pretreatment values of active renin, prorenin and aldosterone and the reduction in diastolic pressure with both nadolol (p less than 0.001) and metoprolol (p less than 0.003). This indicates that the combination of active renin with prorenin and aldosterone is a reliable guide to the hypotensive effects of beta-blockade and that the failure to detect this in previous studies is most likely due to errors in the measurement of renin.