Minimally elevated preoperative parathyroid hormone level influences the management of primary hyperparathyroidism

Objectives/HypothesisTo determine the effect of preoperative parathyroid hormone (PTH) level on the extent of surgery and the accuracy of parathyroid imaging in primary hyperparathyroidism. Study DesignRetrospective cohort. MethodsFinal diagnosis of single-gland adenoma and its location versus multigland disease was established in this retrospective cohort study. Positive predictive value, negative predictive value, and accuracy of imaging were analyzed in relation to preoperative PTH levels. ResultsEighty-seven percent of the 218 patients enrolled in the study underwent unilateral targeted operation and had a 97.9% (95% confidence interval: 95.8%-100%) success rate. However, in patients with PTH <65 pg/mL, 28.6% had bilateral exploration compared to 10.3% in those with PTH 65 pg/mL (P=.042). In patients with PTH <65 pg/mL, 7/21 (33.3%) had inaccurate sestamibi findings compared to 24/174 (13.8%) in patients with PTH 65 pg/mL (P=.047). ConclusionsAccuracy of sestamibi drops significantly, by threefold, in patients with mild primary hyperparathyroidism and PTH <65 pg/mL. Patients with PTH<65 pg/mL have a 2.5-fold higher rate of bilateral operation to identify the hypersecreting gland(s) compared to patients with PTH 65 pg/mL.