Need for Randomized Clinical Trials on Intraoperative Parathyroid Hormone Kinetics

Abstract

T he use of intraoperative PTH testing to assure that no abnormally functioning parathyroids remain in the patient after removal of 1 parathyroid adenoma has slipped into widespread clinical use. In my opinion, this is unfortunate since the outcomes of this strategy have not been subjected to randomized clinical trials. Observational studies from the active, experienced, and world-renowned endocrine surgeons at the University of California, San Francisco have demonstrated less than 50% predictive success rate in patients with double parathyroid adenomas, a 13% falsenegative rate with single parathyroid adenomas, a negative influence of hemolysis on the reliability of IOPTH measurement, and now the suggestion that race and BMI may impact PTH kinetics. I worry about the statistical validity of comparing 28 African American patients with 734 white patients, especially when other variables are in play (BMI, vitamin D deficiencies, and 24-hour urinary calcium excretion). Using IOPTH changes for clinical decision making in the operating room requires expense of time, material, and people, both in the operating room and in the laboratory. Reliability of this strategy suggests that all types of patients with all varieties of hyperparathyroidism would have uniform response of PTH kinetics in a predictable fashion. To me, this seems unlikely. Different anesthetics, length of operation, avenues for blood acquisition (peripheral vein, central vein, jugular vein, or peripheral artery), and operative techniques of parathyroid manipulation might all have effects on IOPTH kinetics and values. Because of their expertise and high volume of cases, the surgeons of the University of California, San Francisco and their cadre of trained fellows would be ideally suited to conduct a randomized clinical study in a standardized fashion that could determine the values, reliability, and costs of using IOPTH strategies vs not using them.