Natural history and complications of normocalcemic hyperparathyroidism: a retrospective cohort study

Abstract

Normocalcemic hyperparathyroidism (NHPT) is variably defined, and information regarding complications and natural history are scarce. We aimed to describe the phenotype of NHPT in relation to hypercalcemic hyperparathyroidism (PHPT) and controls, to determine risk of progression, and to develop a predictive model for progression to PHPT. This is a retrospective chart review of 232 patients at a tertiary medical center, comparing 75 controls, 73 patients with NHPT, and 84 with PHPT. NHPT was intermediate in biochemical profile between controls and PHPT with respect to cCa, iPTH, intraindividual coefficient of variant of cCa, phosphorus, and 25(OH)D. NHPT patients had an increased adjusted risk of urolithiasis (OR 5.34, 95%CI, 2.41-12.71, P