Impact of primary aldosteronism on calcium phosphate homeostasis. Results from the SPAIN-ALDO.

Purpose: To determine the prevalence of hyperparathyroidism (HPT), including primary, secondary and normocalcemic in a cohort of patients with PA of the SPAIN-ALDO registry.

Methods: A retrospective multicenter study of primary aldosteronism (PA) patients followed in 37 Spanish tertiary hospitals and with available information on serum calcium, phosphorus, iPTH, and vitamin D at the time of PA diagnosis. The diagnosis of normocalcemic HPT (n-HPT) associated with PA was based on a iPTH > 65pg/mL with normal corrected serum calcium after excluding the most common causes of secondary HPT, and HPT was classified as secondary (S-HPT) in the presence of chronic kidney disease or vitamin D deficiency, and as primary (PHPT) when iPTH levels >65 pg/mL were associated with high serum calcium levels.

Results: A total of 246 patients with PA were included, of whom 56% (n = 139) had PTH > 65 pg/mL. In the group of participants with HPT (n = 139) the proportion of PHPT was 7.2%, of n-HPT 11.5% and of S-HPT 81.3%. Patients with n-HPT had a higher prevalence of atrial fibrillation (7.9% vs. 1.9%, P = 0.04) and hypokalemia (71.6% vs. 46.2%, P < 0.001) and greater aldosterone (33.2 vs. 26.8 ng/dL, p = 0.003) and 24 h urinary calcium excretion ( 243.5 vs. 160.5 mg/24 h, p = 0.01) than patients without hyperparathyroidism. No differences in surgical outcomes (biochemical and clinical response) were detected between patients with and without hyperparathyroidism.

Conclusions: HPT is a frequent condition in patients with PA and S-HPT is the most common etiology. Patients with HPT have a higher prevalence of atrial fibrillation and hypokalemia and a more severe PA than those without HPT. However, no differences in surgical outcomes were reported between patients with and without HPT.