Hyperparathyroidism in patients with overt and mild primary aldosteronism

Increased prevalence of hyperparathyroidism (HP) has been observed in primary aldosteronism (PA) patients. However, HP prevalence in milder forms of PA has not to date been evaluated.

The objectives of this study were to assess the prevalence of primary and secondary HP in overt and milder misdiagnosed cases of PA and to investigate the effect of treatment on parathormone (PTH) secretion.

Seventy PA patients with normal renal function were included prospectively. Specifically, patients with biochemically overt PA (increased basal aldosterone/renin ratio (ARR) and a positive diagnostic suppression test (DCVT)) and patients with mild PA (normal basal ARR and a positive DCVT) were analyzed. Mean blood pressure and mineral metabolism were evaluated at diagnosis and after treatment.

Primary and secondary HP were found in 4.3% (3/70) and 51.4% (36/70) of patients, respectively, and biochemically overt and mild PA in 47.1% (33/70) and 52.9% (37/70) of patients, respectively. Sixty-three PA patients were followed up after treatment without receiving calcium or vitamin D. There was a decrease of mean blood pressure (p < 0.001), PTH (p < 0.001), and 24-h urinary calcium (p < 0.001), and an increase of serum potassium (p < 0.001) and calcium (p = 0.018) levels in secondary HP patients. There was no significant difference between biochemically overt and mild PA patients as concerned serum PTH, calcium, and 25-hydroxyvitamin-D levels either before or after treatment. Aldosterone levels before treatment were positively correlated with serum PTH levels.

HP prevalence was high in both overt and mild PA patients, whereas the effect of treatment on serum and urinary calcium and PTH levels was similar in both groups.