Diagnostics
A Two-Stage Prediction Strategy for Primary Hyperparathyroidism
By Ruisi Chen, Min Ren, Jingyan Chen and 1 others.
Abstract
Background
Primary hyperparathyroidism parathyroid hormone (PTH) hypersecretion is difficult to recognise when calcium is normal and difficult to distinguish from secondary hyperparathyroidism once PTH is found to be elevated. These are separate problems arising at separate points in care. We developed and evaluated two interpretable models corresponding to these decision points using an internal–external validation design.
Methods
We analysed 2788 adults undergoing PTH testing across three campuses of one hospital (development n = 1843; internal–external validation n = 445 and n = 500); those with an estimated glomerular filtration rate below 30 mL/min/1.73 m2 were excluded. PHPT was adjudicated in 504 (18.1%) by two endocrinologists using biochemistry, imaging and histopathology. Model 1, for use before PTH is measured, comprised total calcium, ln(alkaline phosphatase) and age. Model 2, developed in the Main campus subgroup with PTH above the reference limit (>65 pg/mL, n = 429 of 623), comprised ln(PTH), total calcium and phosphate.