Importance of dietary salt restriction for patients with primary aldosteronism during treatment with mineralocorticoid receptor antagonists: The potential importance of post-treatment plasma renin levels.

We measured dietary salt intake in 26 patients with primary aldosteronism treated with mineralocorticoid receptor antagonists and evaluated whether plasma renin levels were affected by dietary salt intake pre-treatment and post 6 months of mineralocorticoid receptor antagonist treatment. The dietary salt intake level was calculated using spot urine sodium and creatinine concentrations, body weight, height, and age. The clinical parameters pre- and post- treatment were compared. The systolic and diastolic blood pressure levels decreased, and the serum potassium and active renin concentration increased significantly. Although the dietary salt intake did not change after treatment, the differences in dietary salt intake and active renin concentration pre- and post- treatment were inversely correlated (r = -0.418, p = 0.03). The 26 patients were divided into two groups with active renin concentration levels ≥5 pg/mL (Group 1) and <5 pg/mL (Group 2) after treatment. The Group parameters did not differ pre- and post- treatment. Group 1 evidenced improvements in systolic and diastolic blood pressures, and the potassium level and active renin concentration over time; Group 2 did not. Group 1 evidenced no significant correlation between the differences in dietary salt intake and active renin concentration levels (r = -0.481, p = 0.11) but Group 2 showed a strong inverse correlation (r = -0.7599, p = 0.01). In conclusion, we found that an active renin concentration level <5 pg/mL post-mineralocorticoid receptor antagonist treatment may indicate that salt sensitivity has not adequately improved, emphasizing the importance of measuring plasma renin levels after such treatment.