Bilateral or Unilateral Aldosterone Hypersecretion and Responsiveness to Therapy Are Associated with Differences in Calcium/Phosphate Homeostasis in Patients with Primary Aldosteronism

Introduction Primary aldosteronism is characterized by the autonomous excretion of aldosterone, which may induce bone mineral disorders. Methods A total of 96 patients with primary aldosteronism were analyzed to identify differences in the regulation of serum calcium/phosphate balance between patients with unilateral and bilateral aldosterone hypersecretion and to determine whether or not adrenalectomy or mineralocorticoid receptor blockers affected such differences. Results Serum phosphate concentrations were significantly lower in patients with unilateral aldosterone hypersecretion than in patients with bilateral aldosterone hypersecretion (2.96 +/- 0.45 vs. 3.36 +/- 0.55 mg/dL, p< 0.05), and recovered after adrenalectomy (2.96 +/- 0.45 vs. 3.49 +/- 0.32 mg/dL, p<0.01). In patients with bilateral aldosterone hypersecretion, the baseline serum phosphate levels were significantly lower in responders to mineralocorticoid receptor blocker treatment, defined as post-treatment plasma renin activity >= 1 ng/mL/h, than in non-responders. In responders, these levels tended to recover after treatment. A weak negative correlation between the plasma aldosterone concentration (PAC) and serum phosphate was observed, but there were no associations between the PAC and serum calcium concentration or between the aldosterone renin ratio and serum calcium and phosphate concentrations. Conclusion The effects on calcium/phosphate homeostasis may differ according to the primary aldosteronism subtype.