The CaPTHUS score as predictor of multiglandular primary hyperparathyroidism in a European population

Focused parathyroidectomy has been proven to be a safe technique for the treatment of single-gland primary hyperparathyroidism (PHPT). The CaPTHUS scoring model has been reported to be an accurate preoperative diagnostic tool for distinguishing single-gland (SGD) from multiglandular disease (MGD), including preoperative serum calcium and PTH values plus ultrasound and Sestamibi scanning. The purpose of the present study was to validate the CaPTHUS model for the population in southern Europe, since the North American and the European populations show different clinicopathological profiles in PHPT.

This is a retrospective review of a prospectively maintained database of patients diagnosed with PHPT who underwent surgical treatment in a single referral center. Differences between SGD and MGD groups were analyzed using chi-square and Fisher's exact tests for categorical variables and Student's t test for continuous variables. Overall diagnostic accuracy of the scoring model was assessed by the area under the receiver operating characteristic (ROC) curve (AUC). A p < 0.05 level was accepted as significant.

From January 2001 to November 2014, 241 patients were included in the study, of whom 92.1 % had SGD and 71.8 % had a CaPTHUS score ≥3. SGD was distinguished from MGD (p < 0.001) using the dichotomous scoring model based on an AUC value of 0.762. Scores ≥3 had a sensitivity of 76.5 % and a positive predictive value of 96 % for SGD.

Despite good test performance, a CaPTHUS score ≥3 does not discard MGD definitely. Intraoperative adjuncts are still needed to further reduce the risk of missing MGD during selective parathyroidectomy.