Given the established associations between parathyroid hormone (PTH) excess and hypertension1-4, as well as the relationship between primary aldosteronism (PA) and hyperparathyroidism (hyperPTH)5-7, we sought to investigate the proportion of patients with hyperparathyroidism who meet the Endocrine Society criteria for PA screening. We will compare patients with hypercalcemia to those with normocalcemia, and examine the relationships between PTH, calcium, potassium and blood pressure.
This multi-centre retrospective cohort study included patients who attended outpatient endocrinology and bone health clinics at three tertiary health services in Victoria, Australia between 2015-2019. Patients were included if they had parathyroid (PTH) level above the lab specific reference range and were excluded if they had a documented secondary cause of hyperparathyroidism, including Vit D <50nmol or eGFR <60ml/min. Medical records were used to collect demographic, blood pressure and PA screening data as well as biochemistry.
Of 275 patients included in our analysis, hypertension was present in 51.6%, with 62.4% in patients with hypercalcemic hyperPTH compared to 35.5% in those with normocalcemic hyperPTH. In the overall cohort, 15.6% had a guideline indication for PA screening, including 21.8% in those with hypercalcemic hyperPTH and 6.4% in those with normocalcemic hyperPTH. Only 9.3% (4/43) of those with an indication were screened and one was diagnosed with PA. The most common indication for screening was a history of hypertension and hypokalaemia, 38.9% (14/36) in hypercalcaemic hyperPTH vs 28.6% (2/7) in normocalcaemic hyperPTH. We found a positive relationship between serum corrected calcium and systolic blood pressure (p=0.001). There was no clear relationship between PTH and blood pressure or potassium.
PA screening should be considered in those with hyperparathyroidism and hypertension. However, the role of routine screening is patients with hyperparathyroidism is not clear because hypercalcemia per se is a cause of hypertension. Future prospective studies are required.