Hyperparathyroidism can be useful in the identification of primary aldosteronism due to aldosterone-producing adenoma

Hyperparathyroidism represents as a novel feature of primary aldosteronism (PA). Its occurrence in patients with the surgically correctable aldosterone-producing adenoma (APA) and not in those with bilateral adrenal hyperplasia suggested that the measurement of parathyroid hormone could help in differentiating between these subtypes of PA. To test this hypothesis we measured the plasma levels of intact parathyroid hormone, Ca(2+), and several markers of calcium/phosphorus metabolism in 132 hypertensive patients, including 74 with primary (essential) hypertension and 58 consecutive PA patients. Of the latter, 46 were conclusively diagnosed as APA (by finding of lateralized aldosterone excess, pathology, correction of the hyperaldosteronism, and evidence of a fall of blood pressure after adrenalectomy) and 12 as bilateral adrenal hyperplasia. Based on these diagnoses we used the area under the receiver operator characteristic curve analysis to assess the accuracy of serum parathyroid hormone for identifying the PA cases in the whole group and for distinguishing between APA and bilateral adrenal hyperplasia. In this selected population of hypertensive patients for identifying PA cases, the accuracy of serum parathyroid hormone tended to be lower than that of the aldosterone:renin ratio. However, for discriminating between APA and bilateral adrenal hyperplasia patients it was better than that under the identity line and also that for the aldosterone:renin ratio for pinpointing APA cases among patients with PA. Hence, these findings indicate that raised serum parathyroid hormone levels are a feature of APA that can be useful for selecting the PA patients to be submitted to adrenal vein sampling.