Focused parathyroidectomy for primary hyperparathyroidism (pHPT) in patients with a single positive localizing scan may have an unacceptably high recurrence rate unless intraoperative parathyroid hormone (ioPTH) is used. The CaPTHUS score was previously developed to predict singlegland disease in such instances. We evaluated the accuracy of this model in a cohort of patients with pHPT in the UK.

CaPTHUS scores were calculated from prospectively collected data on consecutive patients undergoing surgery for pHPT [(1 point each for: Preoperative calcium ≥3 mmol/L; PTH ≥2 times upper limit; ultrasound (1 point) and sestamibi (1 point) positive for single enlarged gland; concordant positive scans]. Diagnosis of single or multigland disease was confirmed on pathology.

From June 2007 to October 2011, 324 patients (251 female, median age 66, 10.89) underwent surgery for pHPT guided with ioPTH. Single-gland pathology was observed in 291 (89.8%) patients and multi-gland disease seen in 33 (10.2%). In single-gland disease patients, significantly higher preoperative calcium (p = 0.030) and PTH levels (p = 0.033) were seen with sensitivities of 65.6% for ultrasound and 66.0% for sestamibi scanning. A CaPTHUS score ≥3 was seen in 51.2% of all patients with a positive predictive value (PPV) for single-gland disease of 99.4%.

A CaPTHUS score ≥3 was accurate at predicting single-gland disease in >50% of patients with pHPT, providing a similar PPV and reducing the need for ioPTH implementation in this population. However, recent conflicting literature suggests the CaPTHUS score may not be universally applicable, local audit is recommended before implementation.

James TW, Stechman MJ, Scott- Coombes DM. The CaPTHUS Scoring Model revisited: Applicability from a UK Cohort with Primary Hyperparathyroidism. World J Endoc Surg 2017;9(1):7-12.