Investigating intraoperative parathyroid hormone criteria for enhanced accuracy and surgical success in treating primary hyperparathyroidism: results from two tertiary referral centres

Background: Primary hyperparathyroidism is a common endocrine disorder necessitating surgical intervention for definitive treatment. Measurement of intraoperative parathyroid hormone (ioPTH) has revolutionized surgical management, but interpreting the results remains a subject of debate. This retrospective study, evaluated the efficacy of the Miami criterion (a > 50% decrease in ioPTH level 10 minutes after parathyroid removal) in predicting surgical success and whether meeting this criterion reduced persistence rates. It also investigated whether achieving a drop in ioPTH concentration to within the normal range, either alone or in combination with meeting the Miami criterion, led to improved outcomes. Methods: A retrospective analysis was conducted on patients with primary hyperparathyroidism who underwent surgery at two Italian tertiary referral centres. Univariate and multivariate analyses were used to identify predictors of persistence. The diagnostic performances of both ioPTH criteria were assessed, individually and in combination. Results: Data from 380 patients were analysed. Multivariate analysis confirmed the efficacy of both ioPTH criteria, showing a negative association between persistence and both a fall to within the normal range (P = 0.005) and a > 50% decrease in ioPTH level (P = 0.039). The > 50% reduction in ioPTH criterion demonstrated higher sensitivity (95.0%) and lower specificity (45.0%) than the normalization of ioPTH criterion (sensitivity 81.1% and specificity 60.0%). Combining the two criteria resulted in the highest sensitivity (97.5%) and an improved negative predictive value (55.0%) compared with each criterion alone, resulting in the highest accuracy. Conclusion: A fall in ioPTH level to within the normal range helps prevent persistence, whereas a drop of > 50% reduces the rate of unnecessary bilateral neck explorations. Combining the two criteria yields the best results in terms of predicting surgical outcome.