Analysis of Preoperative Predictors of Single and Multigland Primary Hyperparathyroidism

Introduction: Preoperative differentiation of single-gland (SG) versus multigland (MG) primary hyperparathyroidism (PHPT) can assist with surgical planning, treatment prognostication, and patient counseling. The aim of this study was to identify preoperative predictors of SG-PHPT. Methods: Retrospective analysis of 408 patients with PHPT who underwent parathyroidectomy at a tertiary referral center. Comprehensive preoperative parameters, including demographic, laboratory, clinical, and imaging results were analyzed. Univariate analysis and binary logistic regression identified preoperative predictors of SG-PHPT. Receiver operator curves were used to analyze the predictive values of existing and novel preoperative predictive models. Results: Elevated parathyroid hormone (PTH) (99.1 pg/mL in SG versus 93.0 pg/mL in MG), elevated calcium (10.8 mg/dL in SG versus 10.6 mg/dL in MG), lower phosphate levels (2.80 mg/dL in SG versus 2.95 mg/dL in MG), and positive imaging (ultrasound 75.6% in SG versus 56.5% in MG; sestamibi 70.8% in SG versus 45.5% in MG) were significantly associated with SG-PHPT. The Washington University Score (a predictive scoring system made from calcium, PTH, phosphate, ultrasound, and sestamibi) and the Washington University Index ([calcium × PTH]/phosphate) were comparable to previous scoring systems used to predict SG versus MG-PHPT. Conclusions: The association of lower phosphate with SG-PHPT is a novel finding. Previously identified predictors of SG-PHPT, including elevated PTH and positive imaging were confirmed. The Washington University Score and Index are comparable to previously described models and can be used to help surgeons predict if a patient may have SG versus MG-PHPT.