Plasma aldosterone concentration and plasma renin activity in untreated hypertensive patients: gender differences and therapeutic implications.

The renin-angiotensin-aldosterone system regulates blood pressure and is influenced by antihypertensive therapy. We examined plasma aldosterone concentration (PAC), plasma renin activity (PRA), and clinical characteristics in untreated hypertensive patients without primary aldosteronism, followed for 3 years. Among 456 newly diagnosed patients, 397 (219 males, 178 females) were analyzed after excluding those with low blood pressure, suspected primary aldosteronism, or renovascular hypertension. PAC and PRA were measured at baseline, and clinic blood pressure was monitored at 3 months, 1 year, and 3 years. A high PAC/PRA ratio (>200) was found in 19.6% of patients and was significantly associated with female sex (p < 0.0001) and higher serum sodium (p = 0.0004). PAC did not differ between groups, but PRA was markedly lower in the high PAC/PRA group (p < 0.0001). Multivariate analysis identified female sex as the only independent predictor (p < 0.0001), with prevalence rates of 29.8% in females and 11.4% in males. In females, PAC/PRA correlated positively with sodium, while PRA correlated negatively, relationships not observed in males. Mineralocorticoid receptor antagonists (MRAs) were used as first-line therapy in patients with high PAC/PRA. Their blood pressure declined from 159/95 mmHg at baseline to 137/80, 135/78, and 133/77 mmHg at 3 months, 1 year, and 3 years, respectively. In the normal group, values were 159/96, 142/81, 138/77, and 136/77 mmHg, with greater systolic reduction at 3 months in the high PAC/PRA group (p = 0.03). We identified gender differences in the renin-aldosterone-sodium system. MRAs effectively reduced blood pressure in patients with relatively low PRA levels.